I recently ran a circuit for a vehicle lift for a guy's shop. When I first looked at the lift I had no specs only the info plate on the motor which stated that it could be ran on either 208-230V @ 17.8-16A max load single phase. I installed the circuit which is 50' from the panel as a 20A and I got a voltage reading of about 243V. I received a call from the owner who said after installing the lift they plugged it in to run it and it will only get about a foot off the ground before it trips and the motor gets extremely hot in that short period of time. I went back there and put my amp meter on it and it spikes as soon as the lift is engaged, I then put a 30A breaker in just to see if I could get an amp reading, which did the amp reading was up around 28-29A the lift would operate but once again get extremely hot. It was then that I saw the manual and started to read through it and that is where I seen that the motor was wired for 60Hz and cannot run on 50Hz without physical change to the motor. I am not sure what Hz reading is for his electrical service at his house. My question is could this be the reason for the high amp reading and extreme heat being generated?
Hz Measurement Question
- Thread starter mmas0n
- Start date
- Status
- Location
- Massachusetts
If you are in America it is 60 Hz + or - very little.
A motor marked 208-230 is made to run on a 240 volt service.
Is it a 208-230 / 460 volt motor?
I would look for misconnections at the motor.
A motor marked 208-230 is made to run on a 240 volt service.
Is it a 208-230 / 460 volt motor?
I would look for misconnections at the motor.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
As iwire said, there is no other frequency available in the US so no need to measure it; it's 60Hz. Besides, getting 50Hz would make the motor weaker but would not likely account for nearly doubling the amp draw. Assuming it's a hydraulic lift, most likely something in the hydraulics is busted. If hydraulic fluid can't move from a hydraulic pump, it's not like a centrifugal water pi]mp that just spins unloaded. A positive displacement pump used for hydraulics would immediately go into locked rotor if the fluid can't flow. A partial blockage might account for what you are seeing here.
For the same voltage, 50Hz would result in a 20% increase of V/f which could maybe result in saturation. But it's a bit academic if the motor is being operated from a standard US supply.
brian john
Senior Member
- Location
- Leesburg, VA
CAn you isolate the motor from the pump and run it. To verify if it is a motor issue or a pump issue?
broadgage
Senior Member
- Location
- London, England
As others post, if from the grid the frequency will be 60 cycles (or very close) in the USA.
If from a generator, it could vary, but probably not enough to matter.
I would suspect a mechanical problem, or mechanical overload of the lift, or if this is a used machine, the wrong electric motor fitted.
If from a generator, it could vary, but probably not enough to matter.
I would suspect a mechanical problem, or mechanical overload of the lift, or if this is a used machine, the wrong electric motor fitted.
boboelectric
Senior Member
- Location
- Eighty Four,Pa.15330
The last electric car lift I did,I ran a 240 /20 amp feed to the location,the install crew took it from there. I'd be off the hook.
- Status