How to make a SILENT Huanyang Variable Frequency Drive. 

I am really glad you found it useful. My Huanyang VFD is still going strong despite almost never having the fan working. Many people predicted that it would be ruined because of the modification. I think the fan has only ever cut in four or five times and it was always on a very hot day and usually when I was doing some high torque drill processes. Regards, Mark

That's great! I don't regret delving into the guts of my Huanyang. However, I recently purchased two Bosch Rexroth VFD's and they are only slightly dearer that the Chinese VFD's and as a bonus, you can turn the fan off or on or set it to auto in the configuration menu. Regards, Mark

Ken, that sounds like a good plan. I must admit that on/off circuits are about as adventurous as I want to get when messing with mains operated gear. The VFD runs really well on my smallish drill press as it doesn't run for long and most times it isn't running particularly hard. I have had the fan cut in on a few occasions and that was when it was quite hot in the workshop and I was drilling lots of holes or large holes. I would think if you were using the VFD to power a pump or a large conveyor or something like that you wouldn't want the fan to be off at all. Running in standby mode as you suggested would be good. Regards, Mark

The noise of that fan used to really annoy me. Since doing the mod it has only ever run twice. On both occasions I was drilling lots of large diameter holes and it switched off after about 10 minutes. Some one recently pointed out that if the thermal switch fails it won't be obvious and the drive might fail due to overheating. He suggested I use a normally closed switch but It would make the switching more complex. I prefer my more expensive VFD's but the Huanyang works fine on the drill.

@@Preso58 Rather than changing to a NC switch you could just add another NO switch in parallel to the one that you have. So far I have had no problems with my Huanyang, the general concensus seems to be that it is the best of the oriental offerings. As I am sure that you know the manual is total rubbish and the programming is tedious. BTW I ordered a bunch of 45 deg switches which should be here in a day or two. My lathe motor has a noisy fan powered by it own motor, that fan is far worse than the VFDs and I'll be controlling that fan as per your suggestions as well as both VFDs. regards Tony Foale.

Maybe I'm missing the point, but in my experience, as I get older, I cannot hear those annoying high frequency pitches. Everybody else is hugging the floor screaming "Phaser on overload!" and I'm just wandering around clueless. Who says a 360 watt car stereo system in 1986 can cause hearing loss...

Ha ha, I sort of came to the same conclusion after I spend so long delving into the guts of the box. There's no shame in taking the course of least resistance. Well done.

I have the same drive. Switches on their way from China. Thank you for this tip! I will definitely do it. I was considering switching the fan to something bigger and laying it on top. Did you consider that @Andrew George?

Paul, I agree with your observation that time spent on upgrading inferior design has it's own merit. I take the view that even if I end up scrapping the part I have at least learned something that I otherwise would not have known. Also it is very satisfying when a project turns out to be a success. I rarely have the fan in the VFD turn on now and when it does I am reminded that the mod is working as intended. I am surprised that you were able to buy a cheap Chinese drive that worked straight out of the box and with such a short boot up time. I assumed that all those cheap drives were clones of each other. Mine initially seemed to be broken. The motor would only turn at 100 rpm or so and it sounded like it was very close to death. I found out (on RU-vid) that by default, one of the parameters was set to a ramp up time of something like 5 minutes. So of course it seemed like it was never going to get going. I'd be interested in finding out a link for the "good" VFD if you still have it. Regards, Mark

Can you say which is the drive that worked out of the box with fast boot time?

I'm glad I'm not the only one that was driven crazy by the sound of that little fan whirring away for no reason. Just recently, I had to drill a large number of large holes with a 25mm hole saw and it was a very hot day. I am happy to report that the fan switched on and did it's job although that's probably only the second time I have had the fan switch on since fitting the thermal switch. Regards, Mark

EXACTLY! I had one of these rigged up on a heater and got a shock when the piece of shit engaged.

John, I despair sometimes at how the Chinese manufacturers almost get a good product to market but somehow they seem to fall short for want of few lock washers, a decent paint prep or a lack of deburring on some critical part that takes the skin off your knuckles. Having said that though, I think that we here in the global market are enjoying a golden age of affordable products. I doubt that it will last forever. Regards, Mark Presling

@@Preso58 For the low cost, who gives a shit if it only lasts a few years? Just chop the fan off it and bin it.

@@Preso58 I care how long things last! It seems to me that all the Chinese rarely exports anything quality, except for the quality of JUNK! My opinion, of course.. I am tired of throwing my money at them. Tired, I say! I do feel that this trend is manufactured by their government and not directly by the individuals who produce the items. Their hearts are in the right place, but the business owners are strapped down because of the ingrained fear of their government.

I get the feeling that the fan position and the control for it seems to be a bit of an afterthought on these Huanyang VFD's. The good news is that the fan hardly ever runs since the mod was carried out. Regards, Mark

@Preso58 Totally agree. I just picked up a Harrison M300 lathe, ex RAN training school, and have converted the electrics to 240Vac with 24Vdc control. I've used an Invertek (English made) VSD (similar to the one you've got). Oddly, this drive doesn't have any force cooling, totally dependent on natural convection. Watching all your videos, very informative and interesting. Loved the bridge !

Thanks. I can tell you that the fan on my VFD almost never turns on now. If I am making big heavy cuts with something like a large holesaw, the fan will turn on but it's a blessing to have the VFD turned on and silent. I recently purchased two Bosch Rexroth VFD's and they have options in the setup to turn the fan on permanently, off permanently or set to auto. The default is auto and neither fan has started on them even though one is fitted to my Colchester lathe and it works quite hard sometimes. Regards, Mark

I was dealing with an unknown quantity. Now that I know what is inside I can see that there would be plenty of ways to get the same result without risking the innards by taking it apart. Regards, Mark

With regards to safety, I just went and checked the switches I purchased for this modification and the case is isolated from the two switch wires so there is no danger of line voltage finding its way to the fan. The fan, and its shroud are insulated so once again there is no danger of leaking voltage. I did not really alter any of the structure of the VFD except for drilling one hole in the heatsink. I believe the TO220 package is in fact a heat sensor since documentation states that the digital display is capable of showing the temperature of the VFD however I couldn't find the correct settings to make this happen. So far the mod has been a success and just two days ago I had to drill a large number of holes in some stainless steel sheet and the cooling fan started up as I expected it to but that is the first time I have heard it run since installing the switch.

@@Preso58 Current ads also show the temp sensor so they can compare theirs to a knockoff. Also the HY has two current sensors while the knockoff has only 1.

Hi, Unfortunately there are many variants of the Huanyang VFD. Some are actually clones of the clone and they all seem to have different variations of the plastic housing and protection of the heatsink. In my case the heatsink was pretty much totally enclosed by the plastic housing and I needed to dismantle it to get at the aluminium extrusion. I considered using epoxy to mount the thermal switch but after many heat cycles and differential expansion and contraction I figured that the epoxy would delaminate. This could happen and the operator would be unaware that the switch was no longer attached to the heatsink unless you inspected it. If the glue did fail the fan would not switch on, ever.... and then you could have a situation where it was needed due to excessive heat and it would not do it's job. The little clip that I made was more work but it should never fail. I did actually fit the switch in series with one of the power wires to the fan and I must say the drive is now totally silent but I have had the fan cut in, once. It was quite hot in the workshop and I had just finished drilling a large number of large diameter holes in some stainless steel sheet using a big step drill. The fan ran for about five minutes and then, like magic, it stopped again. I am guessing that you were lucky that your switch was a nice fit between the fins and this should reduce the likelihood of it getting dislodged. I hope you are enjoying the "sounds of silence". Regards, Preso

@@Preso58 Hi Mark. Pleased to read your feedback ;-) I am not that familiar with different versions of these Huanyang VFDs but the one I bought is a 2.2 kw version (HY series). And I most definitely appreciate the silence - although a CNC mill likely is never silent when used having the fan in the vfd on always without any real need for this really was disturbing. And now it appears to be always silent - indeed a relief! So many thanks for the inspiration - cheers ;-) ... Jesper

I didn't know what i was dealing with when I decided to pull the case apart. I can now see that there were less intrusive ways of installing the switch. Still, pulling things apart is both thrilling and scary at the same time. Regards, Mark

I also hated the sound of that little whirring fan. I knew it wasn't using much power but it just bothered me for some reason. Probably because I knew it was unnecessary for it to be running when the drill wasn't operating. Regards, Mark

Thanks, I can tell you that the fan in my VFD has only ever started up once after I drilled a large number of holes with a step drill through some aluminium tubing on a very hot day. Other than that I never hear it run. Having said that it would depend on the application. Drill presses tend to run intermittently and often they do short runs at light duty. It might be different for applications like pumps or large fans. Regards, Mark Presling

@@Preso58 How did you come up with 45c being the right number for the sensor on this? Just a guess? What if they are meant to run cooler than that?

@@Sugarkryptonite it was just an educated guess. I actually bought several different sensors with varying temperature ratings. I chose the 45C because that's about the temperature in the workshop on a really hot day and as it turns out it is about right. The fan rarely turns on and the VFD is still going great after nearly three years of use.

Precisely what I was going to recommend.

I agree that Noctua is a good brand, I myself replaced noisy fan in my 3D printer that had been actually replaced already once before with cheap crap that broke again, no issues with noctua so far and very silent. But they don't achieve it with some magic technology, if you put chinese $1 fan next to noctua $10-20 fan and spin both at the same RPM, they will create pretty much same noise and noctua just few dB quieter at most. What they do to achieve most of the difference is to reduce the RPM, this means that the amount of air that those can push is reduced as well. This means that whatever you're trying to cool, Noctrua will cool it less, in worst case your device might overheat. So be aware of this and check the temperatures before and after to make sure all is good.

I have recently purchased two Bosch Rexroth VFD's and the fan can be set to three different modes in the parameters. Always on, always off or auto which I assume is temperature dependent. The fan on my Huanyang almost never starts unless it is a very hot day and I am using some big drill bits or holesaws. It seems to suggest that for intermittent use, the fan is mostly redundant. Regards, Mark

Thanks, I'll keep that in mind. So far I have not heard the fan switch on once and I did some fairly heavy drilling operations for another video I was doing. I have also been monitoring the motor temperature (by holding my hand against the frame) and for what I am doing, it never gets more than warm. I can imagine that in an industrial environment it would be a different ball game all together.

higher switching frequency (carrier frequency) does result in more heat generated in the motor and the VSD, it's the number of times the IGBT's are switching on and off per second, the transition from off to on and on to off is when IGBTs generate heat on the heat sink. You can safely go higher on smaller VSDs generally speaking, 12 or even 16kHz shouldn't be an issue. A plastic extruding machine would be constant torque load and typically at full rated load of the motor most of the time. Bigger VSDs over about 110kW do not usually run a switching frequency above 2 or 2.5kHz in my experience. (almost a decade in VSD service).

Arri, I have only ever had the fan start up once after I had drilled a number of fairly large holes with a holesaw. It was also a fairly warm day but now I can leave the VFD on for extended periods with it just idling and it is still functioning perfectly. Regards, Mark

@@Preso58 Good to know!

I would like to put a resistor across my thermo switch. Did you figure out what you needed to make the fan spin at a slower speed? I also thought about sending power to the fan when I am drawing power from the VFD but I haven't figured out which terminal to use for power or how to program a terminal to deliver power.

Well, as it turns out, the fan hardly ever runs. It has only switched on a few times on really hot days when I have been drilling a lot of large diameter holes. It will run for about 20 minutes and then shut down. Regards, Mark

Thanks for the feedback Tom. I did notice what looked like a temperature sensor but I don't know enough to reverse engineer what it might be for. I will have a look at the manual to see if there is anything in there about controlling the fan but, you know, the translation is difficult to follow. Regards, Mark

@@Preso58 oh yes....the mauals....crazy....I stay in a constant state of frustration, plus I am not the electronics wizard. I must apologize about the 2.2kw unit I have. It does have the same fan and does make some noise. I just didn't realize how much until you called that out....😁. Very sorry to mis-inform you. I was going on memory when I sent you the note. Thank you for you most wonderful, methodical, and professional actions (I mean that). -Tom

I have had a lot of viewers suggesting that I should swap out the fan for a different type but at the end of the day, having done the mod on the drive, the fan hardly ever runs. For the application that I am using it for, the drive hardly ever works very hard so having it remain completely silent is a bonus. It also saves energy! Although the drive is inferior to my better quality Invertek VFD, it was half the price and it's still working perfectly. Regards, Mark

Thanks Jan, I didn't expect that I would be connecting this VFD to a CNC controller but it might be relevant for others. Regards, Mark

Arri, thanks for that. I must say I was so grateful when I found a way to shut it up that I just left it alone after that. Regards, Mark

Cool! I hope it works out for you. I know that since I have done the mod on my drive the fan has never cut in and the drive is still functioning perfectly. Good luck.

Thanks. To quote Jessie Pinkman "Yeah, science bitch!" 😁

Derek, Hope it works for you. It certainly seemed to be a successful modification for my shop. Cheers.

Don’t it will break it

That is exactly what I am starting to realise. Since fitting the temperature sensor I have never had the fan start up so the heatsink is never getting more than warm during the times I use the machine.

I’ve got a leeson vfd that also has a constant loud fan, when it’s first started and it’s cold the bearings get rough and the fan slows down and makes a grinding noise (just like both my welders lol). Only part that gets warm is the plastic over the capacitor bus

You complain about 7 seconds of music???

@@Watchyn_Yarwood Not so much a complaint, but some input on what I liked or didn't like about the video. Notice that my comment got a few thumbs up. So some other people probably agree with my comment. If my comment got lots and lots of thumbs up, then the author of the video might consider making changes to future videos, to get more views/subscriptions/likes.

The manual that comes with most of the Chinese VFD's are not exactly well written but there is a wiring diagram in the front of the book that is fairly easy to follow. Some of the Chinese VFD's come preconfigured with a very slow ramp up time which makes it seem like the motor or the VFD is faulty. Changing just that one parameter makes all the difference. Regards, Mark

As it turns out, the fan almost never starts up on this VFD since including the thermal switch. Probably because the drill motor is only used intermittently and it's generally only lightly loaded. If the drive were running a pump or a fan it would probably get hot enough to need the extra cooling. I was drilling a lot of holes with a large holesaw on a fairly hot day and the fan did kick in but that's probably the only time. Regards, Mark

I guess it's a sort of OCD thing. I sometimes walk out and forget to turn the drill off at the wall. I would worry about a fan running non stop overnight. Until I dismantled the case I didn't realise how deep I would have to go into the guts to mount the thermal switch and I was pretty much committed to the mod by then. The good thing is that the fan does do it's thing if I run the drill hard and the rest of the time it just sits there and behaves itself. Regards, Mark

The thing is, at 60 years of age, I do actually like listening to dub step. I have a son who used to change my shop radio to the local "youth" station and after a while I gave up changing it back to "my" station and now I only listen to hip hop, indie, grunge and electronica. I was kidding about the thrash metal though. I can't stand that crap.

Yes, a quieter fan would be better than having the noisy fan that the VFD came with but in reality the fan is almost never needed. I have only ever had the fan operating on a few occasions when it has been very hot in the workshop or when the drill press has been cutting a lot of very large holes. I guess it cuts down on electricity costs too. Regards, Mark

I recently bought a Bosch Rexroth VFD for my Colchester lathe. It was only slightly more expensive than the Chinese versions but it has a manual written in English and some very cool features. I read some dire warnings about using the variable speed functions of VFD's to control the lathe spindle speed. The issue is that at very low motor speeds the oil is not circulated inside the geared head and it doesn't take long to run the main spindle bearings dry. I set my VFD to run at 50hz and vary the spindle speed with the quick change gearbox. On the drill press it's not really an issue but you are correct about the torque dropping off alarmingly at low frequencies. I ended up fitting a 7:1 pull gear (a planetary gearbox) to the motor to reclaim some torque at the low speeds. Regards, Mark

@@Preso58 I was not after running the motor slower as I wanted to easily increase the speed for facing of larger diameter stock to maintain the quality of cut. It not so much the torque but the current drawn by the motor. I put an ammeter in series with the motor. With just the motor and gearbox spinning the current drawn at 50 hz was a nominal .75A. The rest were, 40hz-2.5A 60hz-1.5A 70hz-3.5A 80hz-4A 90hz 5.5A , around 95Hz the VFD would trip on overcurrent. I didn't measure the power factor so not sure of the actual power. But this was enough to tell me that the motor was not suitable to be run from a VFD. I abandoned the idea as the most I could get was about a 20% variation in the speed. I did a bit more research and to guarantee proper running on a VFD the motor needs to be designed for it (lots of money). It was a single phase 1 HP motor. One day I will do the same testing on a 3 Phz motor and VFD

Merlin, the funny thing is, that since I did this upgrade on the VFD, the fan has never switched on. This makes me think that it is included "just in case" or maybe I don't run the drill for long enough or hard enough to create any heat in the heatsink. I think that in some applications where the motor is running for long periods under high loads then the fan would be needed.

Mark Presling The VFD fan on my bridgeport kicks in all the time when I do long runs under heavy load. Like you said, it comes down to duty cycle. I figured I post those solutions for the heavier users. P.S. Thanks for showing that tangential tool holder in your videos. Been looking to make one and your close ups helped me work out the geometry.

You will need to fit a switch in a remote location or use your existing machine switch and then wire it to the inverter terminal strip. You also need to change some parameters to enable remote switching. This article might help www.hobby-machinist.com/threads/huanyang-vfd-on-a-bridgeport-clone.36144/ Regards, Mark

I must say, this is one of the more successful modifications I have made in my shop to date. The fan actually switched on for the first time a few days ago when I had to drill 64 large diameter holes in some stainless steel sheet with a step drill. It was a fairly hot day too so that might have something to do with it. I also watched a video by rolingmetal who said that his Huangyang VFD blew up and he suspected it was because he had disconnected the fan altogether. At least mine has the fan as backup when it is needed which is apparently not very often. Hope you mod goes well. Regards, Preso

@@Preso58 Yeah honestly I am on my 4th VFD lol because 2 blew up prior

You could do that but the solution I have now means that the fan almost never switches on at all. I think it has run on just a few occasions when I was drilling some large holes with a hole saw and a when I was doing a lot of holes on a very hot day. If it is needed, it cools down relatively quickly. Regards, Mark

Yes, just watched that and it would drive me nuts. It seems like you did get some good advice though. I found that changing the carrier frequency helped with my VFD's.

Man, what's the cost, I mean if it's first generation, it seems like it may have a bit of time on it already, and potentially reaching it's warranty limit.

Good point. The switch I added in should be fairly robust though. No semiconductors to fail.

Maybe, but I wanted to interfere with the VFD as little as possible. I am a bit out of my depth when dealing with the sort of electronics inside one of these things and I knew that if I damaged something I wouldn't be able to trouble shoot my way out of it. Regards, Mark

Many people have asked this. My aim was to configure the fan so that it only ran when necessary. I have some high quality Invertek and Bosch Rexroth VFD's and they can have the fan configured in the settings so that it only runs when the heatsink temperature rises above a preset level, or permanently on or permanently off. Since carrying out the modification on the Huanyang drive, the fan has only ever run on a handful of occasions. Usually on very hot days or when I am using large diameter holesaws for extended periods of time. This sort of indicates that for normal use on a drill press, the heatsink can cool itself using just ambient air surrounding the fins. On day to day use, the fan never switches on at all so I guess it is an energy saving as well. Regards, Mark

@@Preso58 Thanks for sharing .. Stay safe and well...

Mike, since doing that mod I have only ever had the fan turn on twice. On both occasions I was drilling a lot of large holes on a hot day. In hindsight I could have pressed the sensor in between two fins of the heatsink using something like a U shaped spring from stainless steel sheet or brass and then smeared it with some epoxy to keep it in place. I too was a bit apprehensive about digging that deep inside the guts of the VFD but the fins might be easier to get at depending on how your case is designed. The fan on my VFD is easy to get out and the wires come out with it so you don't need to open the case for that step. If you have an external relay capability that would be a good solution. Regards, Mark

Are you sure you have a single phase to three phase drive? I have read that some people inadvertently get hold of a single phase to single phase inverter. They can look identical on the outside. When you open the cover to expose the connections you should see terminals for earth U, V and W. These should be connected to your three phase motor. On the other side you should see terminals for the single phase input, R for active and S for neutral, the earth should be common for both the motor and the input. You also need to make sure you set the inverter with the voltage, base motor frequency and the power of the motor before you try to run the motor for the first time. Regards, Mark

Peter, I converted my drill press to a 240V three phase motor and installed the VFD to give me variable speed. It has a three step poly vee belt drive as well but having the variable speed is great for things like countersinking bits where slow speed reduces chatter. There is very little torque at the lower speeds though. Recently I made and installed a pull gear which gives a roughly 4:1 back gear. Regards, Mark

@@Preso58 thanks Mark. I did not know we could get three phase 240v motors? I think my son may have mentioned it once (he's a sparky) but I would have thought he was talking about 440v as we were discussing a VFD for my mill and its the latter. I'm in WA, what state are you in?

Thomas, I was very keen to have the least invasive fix for the fan that I could. I'm not exactly confident with the sort of electronics that inverters use. I can say that since making the modifications to the VFD, the fan has only ever started up twice. Both times it was a very hot day and I was drilling a lot of holes with large diameter bits. It actually surprised me when the fan started up. It ran for about 30 minutes and then shut down again. So, I am quite happy with how it has worked out. It has proven to be automatic and the VFD is now over six years old and apart from the long boot up time I am quite happy with it. Regards, Mark

I got the sensors on Ebay Australia. Link is here www.ebay.com.au/itm/KSD9700-Temperature-Switch-Thermostat-Thermal-Protector-Normally-Closed-Open-MO/201993260718?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 These are really a heat activated switch. In practice the fan in my drive has never switched on since I installed the switch. I guess it would be interesting to find out the temperature of the heatsink but I am thinking it wouldn't be necessary.

Maybe it's not evident on the video but up close it sounds less shrill. Regards, Mark

I wouldn't think mounting it horizontally would affect the cooling. After I made the modification to the fan power supply I think the fan has only ever started up on two occasions. On both of those times, it was a very hot day and I was cutting large diameter holes with a big holesaw. For normal drilling it doesn't seem to even get warm. However it might be different if you were driving a 2.2kw spindle motor. Regards, Mark

@@Preso58 thanks for the prompt response Mark. I'll give it a go and see how it turns out. If it gets too toasty then will have to re-strategise.

Unfortunately, the fan runs from a 12V DC rail on the inverter logic board and the spindle in my case is 3 phase AC so it would be necessary to use a relay to make it work. As it turns out, the fan has never actually turned on since I did the mod on this drive. I believe that the heatsink never actually gets that hot with the sort of intermittent drilling that i do. I would think that if you were running a heavy lathe or milling machine spindle you would generate a lot more load and heat but the sensor that I fitted would switch the fan on when it was needed.

Maybe A little rubber wheel mounted in the drill press so when it's turned in, the rubber wheel turns, driving a shaft that comes out the housing of press, flywheel on the other end with a small belt running another wheel on the shaft of the fan. There you go. Not terribly efficient but run off the drill press spindle itself....

Call my stingy but I hated the idea that the fan was just running for hours when the drill press was idle. The noise was a nuisance but it was also just wasted energy. My electricity bill is high enough already. Regards, Mark

@@Preso58 I do realize that there must be motives and there must be some justification for the lost time, at least to oneself. If I were you, I wouldn't mindlessly attach anything else to that part. you could very quickly come up with the fact that this is not as smart as you think. What's the point of saving so that a fan isn't running? That's maybe $5 a year. maybe you could save much more simply by eliminating standby consumption. Nobody has time for that in my workshop, for me it's just a tinkering for its own sake. That's no use, it simply has no added value and nobody should imitate it.

Not that I could find. As you are aware the manuals are not that easy to understand!

@@Preso58 That is putting it mildly. ;-) I have a 3KW unit from them and it does not make as much noise. When you had the fan out, yours was quieter so my guess is that part of the noise of yours is from the housing. As mine is sitting out in the open, it means that it is easier to get at. My fan is directly mounted on the heatsink and has no plastic around it. It is also sold as an updated version and has some things that older ones didn't it seems. Mine can run on 110/120, 50 or 60Hz, and single or three phase. But no fan temp control. It does have 3 rather large capacitors where others I have seen only had two. Now if I can just figure out how the get the built in pot to run at full frequency I'd be all set. Auto run goes to 400KHz while manual only goes to 230KHz. And yes, I can set the upper limit on PD172 to 460.

Mine matches the one dynoguy has in his video except the input voltage. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-9wJI33NhdhU.html

Mark, I live in Australia and my shop power is 240V 50Hz. Regards, Mark

Yes, absolutely. The fan rarely switches on. Just recently we had a really hot day and I was doing some drilling with a 25mm hole saw in some thick carbon fibre. I was surprised when the fan started up. It ran for about 15 minutes after I shut the drill down and went quiet again. I use the drill press almost daily and the VFD has been quite reliable. I used to hate having the VFD switched on before I did the mod on it because the fan was quite noisy. It probably draws very little power but it's a bit like walking into the kitchen and finding the fridge door open. I probably went a bit overboard with mounting the sensor. You could probably just jam it in between two fins of the heatsink with a bit of wood and it would work as well. Regards, Mark

Not really. The whole idea was to eliminate the noise of the fan rather than to reduce it. Since doing the modification, the fan has really only cut in once or twice. Regards, Mark

Paul, I used these - KSD9700 Temperature Switch Thermostat Thermal Protector Normally Closed Open MO. Here is a link to the original Ebay listing. www.ebay.com.au/itm/KSD9700-Temperature-Switch-Thermostat-Thermal-Protector-Normally-Closed-Open-MO/201993260718?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Frank, unfortunately I don't have 3 phase power in my shed. When we built our house we put the mains connection underground and because we were on a tight budget we used the lightest cable we could get away with and the smallest conduit as well. We live on acreage and the house is a long way from the street frontage so short of running 3 phase above ground and putting in several poles, I don't think it's going to be an option. Regards, Mark

Yes, not really a fan of dubstep but my teenage son did change my mind about some aspects of music. My staple used to include Eric Clapton, Emerson, Lake and Palmer, Santana etc. but now I do like Hip Hop and Indie music as well. Who said you can't teach an old dog.....

You can wire in a start stop and reverse switch via the terminal strip inside the bottom cover of the drive. You also need to add a jumper wire between two of the terminals but it's a bit difficult to explain here. If you have the original user manual it will show the function of each terminal and where to add the jumper to run an analogue speed control and the start/stop switch.

Absolutely. My upgrade is still fine after nearly three years of daily use.

@@Preso58 I am surprised, I would installed a small relay to carry the load.... good for you. Good job.

Yes but the goal was to eliminate the noise rather than to subdue it. For my application the fan stays off for 98% of the time that I use the VFD. It only cuts in on really hot days and on the occasions that I cut a lot of large diameter holes. Regards, Mark

Yeah, sorry about that. My pathetic attempt at making a joke.

Well, the fan was fine. It just doesn't need to be on all the time. In fact it has never switched on since I did the upgrade which makes me think that some applications for a VFD don't use enough energy to warrant assisted cooling for the heatsink.

Electric motor....