Testing The MG2 In A Prius With A MEGGER Meter! 

Hey thanks for your interest! Unfortunately I'm not too familiar with the gen 2 inverter. I do believe they are different, similar but not identical. I would search through a website called Priuschat.com. its a forum site dedicated to solely prius's and their issues/fixes. Very knowledgeable folks there and I'm sure you can find a good test procedure to double check your inverter for possible damage. Hope this helps!!

My best guess is due to the inductive nature of the magnetic rotor as the MG2 was still installed in the transaxle when I was running the resistance check across the coils. I'm certain that its not related to a capacitance in that circuit as the only capacitors that I know of are the 3 big ones in the inverter, however I isolated the MG2 such that I may measure specifically it. The meter’s resistance reading function works by applying a small voltage to the circuit being tested and measuring the resultant current coming back from said circuit. If an inductor (in this case, the magnetic rotor) is in series with the resistor, it will oppose changes in the current, resulting in current rising slowly, finally stabilizing with current being limited only by the resistor (with the resistor being the MG2) and since we are measuring a coil, it would make sense that a magnetic field can have an affect on current passing through such a coil and screw with readings.

I ask because I’m working on a 2008 Prius and both mg1 and mg2 had slowly rising resistance and I don’t know whether that’s normal, wasn’t what I expected but it is the first time I’ve used the megger

Of course I’m using a fluke tester and it ain’t as fancy as the one you got either lol

@jeffeldreth7660 hm, that is somewhat suspicious that both have a rising resistance, although I'm unfamiliar with the 2nd generation toyota synergy drive systems found in that model year of prius... they are quite similar but nowhere near identical. This could be a normal occurrence, but my gut is telling me this can't be nominal behavior. I would do a bit more research on your vehicle's specific generation of toyota hybrid system as in the nearly 7 years difference from when the 1st generation system was put in to production (started in '97 through to '03) to when the 2nd gen entered production ('04 through to '09) and a lot of designs were likely modified or revisited to improve the hybrid system for the 2nd gen onwards. And since I don't have experience with anything other then a 1st gen I can't speak too much on issues related to the younger, more refined tech

Though it could also be that its just the meter as well haha