Harman P68 feedmotor not running

[Motormuis]

I have a newer version P68 pellet stove, which has the 6 rpm feedmotor. It stopped running. I took the feedmotor out to check if the auger was stuck. The auger rotates fine without any resistance. I then ran the feedmotor disconnected from the auger in test mode, red feed motor LED is on, all covers are closed. I can hear the motor humming, but it does not run. I measured the RMS voltage on the cables and there is 118V. My initial conclusion was that the reduction gear had failed and offered too much resistance to the motor, but then I connected the motor directly to a 110 outlet via a cable I put together, and it runs fine. Soooo....now I can only think of 1 thing: since the 110V is present, the power supply cannot deliver the current to run the motor. I noticed there is a 6 amp fuse on the control board, but if that would have failed, none of the other motors would run, right? The other motors supplying airflow through the burn chamber and distributing air into the living room run fine. Have you seen this before? What is the fix?
I also noticed there is a slide plate above the Auger at the bottom of the hopper, activated by a lever on the feedmotor assy. I remember looking straight at the auger though on previous occasions when I was filling an empty hopper. How does this slide plate work, why is it there?

 

[David M]

I have a newer version P68 pellet stove, which has the 6 rpm feedmotor. It stopped running. I took the feedmotor out to check if the auger was stuck. The auger rotates fine without any resistance. I then ran the feedmotor disconnected from the auger in test mode, red feed motor LED is on, all covers are closed. I can hear the motor humming, but it does not run. I measured the RMS voltage on the cables and there is 118V. My initial conclusion was that the reduction gear had failed and offered too much resistance to the motor, but then I connected the motor directly to a 110 outlet via a cable I put together, and it runs fine. Soooo....now I can only think of 1 thing: since the 110V is present, the power supply cannot deliver the current to run the motor. I noticed there is a 6 amp fuse on the control board, but if that would have failed, none of the other motors would run, right? The other motors supplying airflow through the burn chamber and distributing air into the living room run fine. Have you seen this before? What is the fix?
I also noticed there is a slide plate above the Auger at the bottom of the hopper, activated by a lever on the feedmotor assy. I remember looking straight at the auger though on previous occasions when I was filling an empty hopper. How does this slide plate work, why is it there?

It very much sounds like the gearbox on the feed motor assembly has failed. When mine went, I could get it doing for a while by tugging on the swing arm, but that would only last a few minutes.

 

[Motormuis]

Status update: From my initial message you can tell that I plugged the feed motor directly into mains, and it ran fine. I did a longer duration test and the feed-motor kept on running for about 15 minutes, pulling about .64 Amps out of the 110 V outlet. Then it stopped and the current went up to 9.5 Amp and the device got warm. Clearly this feed motor is intermittent. Temperature may be involved. I ordered a new one, and it looks from the pictures I saw, that this new one has a fan on the axle to keep the motor cool, something my broken motor does not have. Maybe it is a common failure and the motor manufacturer decided to increase their MTBF by adding the fan

 

[Nitro-Fish]

All of the Auger motors on my stoves (P61's & recently acquired P68's) have the fan on the backside of the auger motor (as well as the combustion blower motor), did Harman suddenly go cheap on both the auger motor and the combustion blower motor with the later models?

 

[SciGuy]

All of the Auger motors on my stoves (P61's & recently acquired P68's) have the fan on the backside of the auger motor (as well as the combustion blower motor), did Harman suddenly go cheap on both the auger motor and the combustion blower motor with the later models?

The official word is they found that the tiny fans weren’t needed.

Hugh

 

[Nitro-Fish]

Yea, kinda like the ones on the combustion blower motors right? I take that to mean they are no longer needed since there is a cheaper alternative, the old style lasted too long!

 

[railfanron]

If a winding on the armature opens the motor will appear to work fine until it stops on the broken section. Then it will not start. Move it to a good winding and it will start fine. It will also overheat after a while cause all the windings aren't carrying the load so essentially the motor has lost part of its power.
Ron