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Honda: EM7000is overload lamp

Fabreezai

Registered
New to the forum, so Ill jump right in!

Em7000is A3
#GCAA-1675680
Overload LED on
Starts, approx 8 sec. shuts down.
E10 and E20 code

Gen set was given to me, been sitting for about 2.5 years.
I have no service manual for this unit.
I understand the codes mean no communications between GCU and inverter.
I am a electrician/electronics tech by trade.
Looking for info on diagnostic measurements:

Test for stator

Test for GCU (if there is one)

Test for inverter (I did manage to find some info on this and it tested good, but not sure if said info is valid)

Would like to use this unit to replace my backup gen set for the house.

Any help/info would be well appreciated!!
 
Last edited:

Vanman

Subscriber
Last Subscription Date
07/10/2019
Sounds like a great deal! Sorry though, I don’t have any knowledge on these machines. Mine are 1960’s and prior. NO electronics! ;) There are others here that are more familiar, just have to wait for them to find your thread.

Oh, and welcome to the ‘Stak! :wave:

Keith.
 

Fabreezai

Registered
Thanks Keith-

I have searched and searched for a answer but no luck. seems like the info I am seeking is closely guarded secret. Maybe all that info was redacted so no one can read it. 🤷‍♂️
 

Fabreezai

Registered
Thanks jerry-
I was hoping someone would be kind enough to help me with this small bit of info to justify keeping the unit before I spent any money on it. Thank you for the link.
 

Fabreezai

Registered
Might be a bad inverter. At least their easy to change
Thanks for your input alex. I also saw that video. Not convinced thats it. I am not willing to use the trial and error method with a $900 electronic part that more than likely cant be returned if thats not it. I’ll do some more tests to be sure.🙂
 

Fabreezai

Registered
D2868B76-B96B-4623-8B45-85BEBC2EE4D3.jpeg
I got the front of gen set apart to do a visual inspection to staor. I dont see any burn marks or anything, does not mean there might not be any coils internally damaged. Still hoping someone will chime in with the test procedure for it. I can then eliminate it as a issue and put the front of it back together.

Thanks guy/gals!!
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
I would be willing to bet that this is an electronic problem, and not a generator problem. That is a robustly simple permanent magnet ac generator, and as you say, all looks well with it.

Keith
 

Fabreezai

Registered
I would be willing to bet that this is an electronic problem, and not a generator problem. That is a robustly simple permanent magnet ac generator, and as you say, all looks well with it.

Keith
Thanks for chiming in again, I agree it does look good, does not mean it does not have a short between phases or a break internally. I did put a ohm meter on it and got the same exact readings no matter the combination of wires, is that right? I would think there would be some slight differences between the coils? 🤷‍♂️
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
Those coils will all be very low resistance, so difficult to measure accurately with an ordinary multimeter. But each winding should be the same. That is a three phase generator, WYE connected, with evidently two sets of windings, right side and left side. So six windings total.

It appears that the right and left sides are not connected together at this point. You can verify that with your meter.

Assuming that is the case, when you measure between each of the three upper terminals on one side you are reading two windings in series. Each of those three readings should be the same.

When you measure between each of those same three upper terminals and the junction of the three windings at the bottom, you should read half as much resistance as the prior measurements. Again, take all readings made with a multimeter with a grain of salt. ;)

Sadly I am of no use beyond the generator and into the electronics. At that point all I know to do is look for burned components or traces. And all that stuff may well be potted for vibration resistance and environmental protection.

Keith
 

Fabreezai

Registered
Keith-
Thanks once again for the input. I will test it this afternoon. Would be nice to eliminate this as the/a issue and put this end back together. Will then have to focus on GCU and inverter. Will post update as to what I find.
 

Fabreezai

Registered
So I Did some testing. I got .5 ohms on each of the 3 phases on both sides, no shorts to ground. So coupled with the visual inspection, do you agree it is safe to assume its all good with this stator?
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
Yep, sounds good to me! Hopefully the electronic side of things is an easy fix.

Keith
 

Fabreezai

Registered
Kevin- Thanks for all of your input in at least getting it to this point of its diagnosis.
Right now its either the inverter or the generator control unit.
Can anyone chime in on the proper procedure to test and eliminate the inverter as a issue?
🍻
 
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