MEP-831A magnet on governor arm not releasing (video)

[Icesythe7]

I picked up this 831a a few months back and the thing ran wide open 24/7 and then the inverter died after maybe 10 mins of use...fast forward to this weekend I purchased a governor controller and new inverter from kurt and have had no issue's runs properly even ran entire house on a 30 min test, however I have been pull starting it as I have not been able to pick up batteries yet. I decided this morning to see how it starts in the cold and jumped it off my 803a and for some reason the arm will not release from the magnet to allow it to run yet if I manually do it it works fine (as shown in video) surely this is not intended operation and was curious if it is not what needs to be done to correct it?

I have adjusted everything per the instructions from Kurt given the new governor controller (5/16 away no load etc), secondly is there a way to test the fan on the back and lid of the machine? I assume they turn on at x temperature but it is so cold here I'm not able to get it hot enough or they are not working.

 

[kloppk]

If starting with the electric starter and you are jumping with a heavy slave to slave cable and the arm does not lift off the magnet when you move S1 to START then it's likely someone messed with the magnet strength on the actuator assembly and increased the magnet strength. Yes, the magnet strength is adjustable! To adjust it you'll need to loosen the nut that secures the magnet assembly to the fixed arm, screw the magnet inside the cylinder in a bit and then re-tighten the nut. You may have to repeat to get the setting just right.

edit: I see you are using automotive jumper cables and misc wires. There may be too much of a voltage drop which could cause the arm to not lift off the magnet. I wouldn't fuss with the magnet just yest. Wait and see if batteries when you get fresh batteries in the 831 if the problem persists.

The two cooling fans are controlled by individual thermostatic switches S20 & S21. One is set to 85F and the other is 110F. They do go bad.

Back of a 110F thermostatic switch part number CA110


You could test the fans by starting the set and then carefully jumpering S20 and S21 to see if at least the fans are good.
*** Be carefull there is 120 VAC on S20 & S21.

Cooling fan and thermostatic switch S20 on back wall


Cooling fan and thermostatic switch S21 on top cover

 

[Icesythe7]

If starting with the electric starter and you are jumping with a heavy slave to slave cable and the arm does not lift off the magnet when you move S1 to START then it's likely someone messed with the magnet strength on the actuator assembly and increased the magnet strength. Yes, the magnet strength is adjustable! To adjust it you'll need to loosen the nut that secures the magnet assembly to the fixed arm, screw the magnet inside the cylinder in a bit and then re-tighten the nut. You may have to repeat to get the setting just right.

edit: I see you are using automotive jumper cables and misc wires. There may be too much of a voltage drop which could cause the arm to not lift off the magnet. I wouldn't fuss with the magnet just yest. Wait and see if batteries when you get fresh batteries in the 831 if the problem persists.

The two cooling fans are controlled by individual thermostatic switches S20 & S21. One is set to 85F and the other is 110F. They do go bad.

Back of a 110F thermostatic switch part number CA110
View attachment 911455

You could test the fans by starting the set and then carefully jumpering S20 and S21 to see if at least the fans are good.
*** Be carefull there is 120 VAC on S20 & S21.

Cooling fan and thermostatic switch S20 on back wall
View attachment 911453

Cooling fan and thermostatic switch S21 on top cover
View attachment 911454

Thanks for the info will go out and test now, the jumper cables are heavy duty, and are going to the normal battery leads on the 831a, the ends are reading 25.4v so I'm tempted to think it is maybe the magnet as when I adjusted as per your guidelines in the instructions I had to set the gap a little wider than 5/16 else the magnet would grab the arm and shut it down.

I just modeled a new load wrench in cad and it is printing to test as soon as it is done I will check the others and report back

 

[Icesythe7]

Just went and tested, I backed the magnet out 1/4 turn and it seems to function perfectly now, the fans both come on when shorted out so either I didn't get it hot enough to trigger them or the switch is broken...I may bring a hair dryer out there and see if I can heat them up, also the wrench worked first try.

 

[Icesythe7]

Didn't want to create a new thread but quick question, has anyone had the contactor drop out? All the fault lights work and I was testing a heavy load the other day and the contactor just dropped out yet no fault lights were illuminated, reclosing the circuit worked fine and it hasn't done it since but just seemed odd it would drop out and not have any faults.

 

[fb40dash5]

Yes, AFAIK that's correct operation- if you apply too much load, the contactor coil circuit opens.

It is kinda confusing, since there's a light for "overload/short circuit" on the fault indicator. I just got my "parts" machine, which runs but has a bad inverter... the overload light is always on with the inverter plugged in... yet I can close the contactor (even though there's no point with no output from the inverter)