Yes, a small control current does directly power the coil and energizes the electromagnet. This is typically supplied from another power source such as a control transformer, power supply, etc...
Love the cut away - picture is worth a thousand words. Audio clarity was excellent, her speech clear, precise, and statements well timed. Always good for relearning where you have to do with multi-disciplined projects. My only suggestion for improvement: add a few callouts to your first stationary image. Some of us feed on nomenclature!
Hein, We hope to make videos explaining both, but as of now the only videos we have on the subject manner are product specific videos. Some of them have some good information and can further help you out with overload relays and protection relays. Just click on the search icon in our main channel page (click on G-TV to the left) and do a search for "protection relay" or "overload relay". I hope this helps.
I need an emergency temperature cutoff switch for a Bitcoin mining machine. What type of switch would I need for 240v 20 a? I assume I would need some sort of thermostat thing that would trip the switch, but not really sure what arrangement I would need. Please help, thanks!
Very good question, functionally they are identical. However a contactor has much higher current capacity then its relay counter part. For example, relays will usually only be rated to 10-20amp contacts. Contactors will be rated to hundreds or even thousands of amps of current capacity through it's main contacts. Both relays and contactors will have coil curcuits rated at 24Vdc, 48Vdc, 110Vdc or ac, 240/480Vac. The only real difference in the coils them selves is the size of them to actuate heavy contacts in contactors or a much smaller coil to activate a relay contact.
I had the run capacitor tested. It was running at about the voltage it should. I replaced it. The symptoms did not. Change. Not sure what you mean about delay system. Symptoms are the same whether it has been on for a long time or whether it has been off for a 12 hours. There is a little circuit board a out 4inches squared connected to the contactor. Could that be the relay system?
Hi Rigel, Our best guess in this situation is that there is most likely an issue with your compressor, which generally requires work from an HVAC professional.
Hi Faizan, Softstarters are made for any HP, and the larger the HP the larger the SS and more the more expensive it is, too. Dol and star delta are different wiring configurations used when line starting large motors. When connected to a Softstarter, we want them connected star or delta but left that way.
You could break 2 of the three poles and equipment would stop, but is not safe to leave power connected to any phases. Is always better to break/disconnect all 3 phases every time you want to stop power, ok?
robviolin1 You would have to look at the contactor specs to see what the peak interrupting current is. Typically it is 150% of the continuous current rating, in which case I would suggest a contactor with a continuous rating of .66 times 500 amps, about 334 amps.
robviolin1 Sure thing. In the example I gave you I have a contactor with a peak rating of 500 amps. In this particular case I am using an ABB contactor as an example. The manufacturer has peak ratings 150% of the continuous. Since 100% is 2/3rd of 150%, I can multiply the peak rating by 2/3rd (.66) to find the contactor rating of 334 Amps. I would then round up to the nearest contactor size. This contactor would be able to handle the continuous rating of 200 amps and the maximum of 500 amps. Contactor manufacturers should list a peak interrupting capacity and since your motor can reach a 500 amp maximum, then you will need to size it base on the maximum.
So what you are saying is to find the correct contactor soleniod for a DC motor, you take the peak of the dc motor which is 500 amps times 2/3 or .66 to get the contactor needed for the motor. It this what you are saying?
My ac contactor was visibly burnt. I replaced it. It worked great for a day. Then it stopped working with same symptoms (wont start). Any ideas anybody?
Hi Rigel, To determine what the problem could be, we should determine if it was the coil that failed or the contacts. If it was the coil, you will want to check the control voltage supplied and make sure the replacement was ordered correctly. If it was the contacts, then we recommend that you check the load for shorts or bad wiring, and also the line feeding it with power should be checked for correct and balanced voltage. I hope this helps get you on the right track.
I checked across both the incoming power and its getting around 246. When the unit is trying to cool the house the terminal that goes to the compressor is arcing. This is the same terminal that burnt out on the old contactor.
Hey Rigel, is this for a home AC unit? If so, it must be a single phase motor in the compressor, and because it is a single phase motor it must have a starting capacitor connected to the “Shaded pole” of the motor that makes it start rotating the same direction each time it turns on. If this capacitor has failed the motor could start in the wrong direction possibly causing this problem, another possibility is the restart delay timer. If the AC system doesn’t have enough time in the off state before restarting, the compressor will lock up from a lack of break away torque. This is common to ALL home AC systems and Refrigerators and Freezers too. You may be best off contacting a heating and cooling service to take a look at your unit, as DIY repairs on these units can be difficult.
You shouldn't need both. You will need a contactor with a motor protection circuit breaker (MPCB) or an overload relay (OLR). The preference between the OLR and MPCB could be the tripping unit needed to close the switch, real estate available, method of control, or cost. It would be a little redundant to have both of these on one contactor.
I use 5 kva contactor in free energy overunity devices because cont have one n half kg weight to lift n no amps I use ten of them in my t magnetic n magnetic contactor engine ten con amps .4 or .3 now u can move any power full engine who gives u 7 to 9 amps 24h input .3 amps output 9 amps so this nine amps is not free .......