MEP-002a and MEP-003a DC Charging System Test

[jamawieb]

I would say yes, if memory serves me the TM say 67 AC volts from stator. Did you take the leads off the terminal block to test the stator while it was running?

 

[juddspaintballs]

I did not. I did not realize I should do that.

 

[Speddmon]

I know this is old. My MEP-003a has 24v DC at the red banded regulator wire with the set off. It also has the same voltage with the set on. The two leads coming from the stator read 22.52v AC between them with the set running. I pulled the blower wheel and cleaned the stator with brake cleaner and I wire brushed the magnet inside the wheel and wiped it clean afterwards. No change in AC voltage coming from the stator. Does this mean I need a new stator?

You do not need to disconnect the leads from the stator to check the condition of it. But, you do need to read the voltage across the two leads...NOT each lead to ground like it appears you did above. You should get about 33 volts as is lists in the check procedure above.

Edit: I didn't notice that you did read the AC voltage across the two leads and only are getting 22 volts AC. Your stator is bad.

 

[juddspaintballs]

OK, I put a NOS stator from Erik's Surplus on. It was sealed in a paper bag with a wax coating when I got it, all wrapped up nicely. Looks to be in good shape. I put it on today. I get ~24v AC between the two leads on the stator. I've already cleaned up the magnet area of the flywheel. Now what? I have 24.08v DC at the batteries.

 

[Speddmon]

I don't remember if there is a way to adjust the stator air gap between the blower and stator or not. If that is not set properly you'll not get the proper voltage. You already cleaned the magnets, as long as they are in good shape that should be good.

I hate to say it, but NOS only means it's never been used, not that its any good.

Since you've gone to the trouble of taking the wheel off and replacing the stator once, it would be nice to be able to get your hands on a known good working one just to borrow and test it out. I am almost positive I do NOT have one in the garage, but I can look.

 

[juddspaintballs]

I see no way to adjust the air gap between the stator and magnets. The magnets are permanently set in the ring that bolts to the inside of the blower wheel. It's a fixed distance and the ring can't move. The stator is also a full circle and cannot move from where it bolts up. A full circle stator inside a full circle magnet seems to me like there is no adjustment. I've adjusted stators on lawnmower motors before and this isn't setup like that.


What could possibly go bad on an unused stator sitting in a sealed package, though?

 

[Guyfang]

Have you performed the checks on the DC charging system that start on PDF reader page 143, of the -12 TM?

 

[juddspaintballs]

Yes. I checked the stator before installing it and had .6 ohms. With the motor running, I have only 22.86v AC between the two stator wires. At that point, it says to notify a higher level of maintenance (AKA, replace the stator or magnets).

 

[Speddmon]

Well, it's either the magnets of the stator again. Pretty simple system. The strength of the magnetic field (flux) is what generates the voltage. If you are not getting the proper voltage it is either the stator or the magnets, it's that simple.