4 Post Lift Troubleshooting

[Cobrargc]

Hello to everyone.

I've got a Dannmar 4 post lift approximately 5 years old. A few years ago I had an issue with the electric motor "shuttering or laboring" to raise with or without weight. Eventually the start capacitor exploded. I replaced the start capacitor and all was well for a couple years.

Recently I'm again having the same "shuttering" issue as before, except the start capacitor didn't grenade this time. Instead it kicks out my 20 amp gfi breaker. It will run, although laboring and slow, and trip the breaker after 15 seconds or so. I replaced the start capacitor again but it didn't help. I have a new run capacitor that has yet to arrive.

I've been using a heavy gauge extension cord to power the lift from day one as the outlet is 20 feet away. The below link to a video doesn't seem to show the motor shuttering much because of my hand movement but you can tell by the sound that the motor isn't running smoothly.

http://s774.photobucket.com/user/Cobrargc/media/20150816_105635_zpsnblkrwvc.mp4.html

 

[matt_i]

GFI does not like current "leakage" to ground. This might point at a degradation in the motor windings.

What I would do is to separate the motor from the hydraulic pump (remove coupler, etc) and try to run the motor independently under no-load.

The other thing to look at is the switch. Where I work we have a 2 poster which is just a momentary "heavy duty switch" (running 220vac). I would remove voltage, check continuity and move it around to see if there is any high resistance readings that might emanate from burned contacts. You could simply order a new one as a "shotgun fix" (iow throw parts at it). The motor could be attempting to run on a reduced voltage.

 

[Serj_DMR]

Cobra,

The problem may have several solutions here. There is a chance that the capacitors you mentioned may be leaking in some way and tripping the breaker. That second cap you mentioned should eliminate that as an issue as you already replaced the first. There is the possibility that there is a loose connection or winding in the motor causing it to trickle a little current back in, tripping the breaker too. Finally, the motor as it has aged, may be drawing more current after the start cap has discharged. Maybe swapping the breaker for 25 or 30 amps?

I know that the motor will spike when it first starts and that as motors age, they can start slowly drawing more current for various reasons (bearing wear, insulation wear/loss, etc). I would recommend getting an in line ammeter and seeing how much you are drawing on your setup before calling one component or another busted.

If that reads under the limit, then perhaps we can discuss further with our motor manufacturer and find out the best course of action here.

Let me know how it goes.

-Serj
Dannmar Tech Team