How to add additional cooling to motor

[CREF]

The hoist motor on a monorail crane occaisonally overheats during heavy use in hot weather. We have no easy way to cool the building or upgrade the motor.

I'm hoping to find a simple way to provide additional cooling to the motor. We will attempt to add fan to circulate more air around the motor, but I am not optimistic this will help.

We have some power available but not a lot of room. We have no way to get compressed air or water to the motor since it is on a crane trolley.

 

[TurbineInvention]

Is this an old motor?
90% of electric motor failure is due improper lubrication. If dirt gets inside the windings it will cause hot spots and make the motor over heat. This may be more of an issue if the ambient is high. Taking the motor apart and cleaning it may help.

 

[CREF]

It is not very old and is TEFC and is probably not dirty based on no history of this. The motor doesn't fail it just shuts down due when RTD (or thermistor?) hits its trip point.

It happens when there are a lot of start/stops and heavy usage in warm weather. Hoping to knock temeprature down a little so we don't hit the trip point.

 

[MikeHalloran]

Does it already have a VS drive or soft start? Consider it.




Mike Halloran
Pembroke Pines, FL, USA

 

[MintJulep]

Across the line starts generate lots of heat. It this a replacement motor? Most crane motors are built to deal with the frequent starts typical of cranes. Are you a victim of "a motor is a motor"?

TEFC makes little sense for a crane because the fan is not on when the motor is not on.

 

[EdStainless]

Soft start and a fan that runs for 15 min after the motor is shut off would both help. You might need to build a duct for the fan to make sure that the air does some good.
I am with MJ on this, it sound like your motor isn't rated properly.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[CREF]

You are correct it is not TEFC.

The duty cycle of the crane was not specified correctly and we are using it at or slightly beyond its rated duty cycle.

We are trying to figure out how to mount fan. There is not much room. I think that is the best solution though.

 

[IRstuff]

Since the system is on a rail, have you consided putting the cooling system at the end of the rail and running dryer vent tubing to the motor?

TTFN

 

[chicopee]

The last company I worked for had three subsidiaries and between these four companies without exaggeration we had over 4 dozen cranes and hoists. We went to all sorts of equipment auctions to buy such lifting equipment and then we would refurbish them, shorten and lengthen spans and install them in our facilities. We never had an overheating condition. So my question is, is it possible that you monorail crane may have been put together from miscellaneous parts and inadvertently the wrong size(under rated) motor was used? Because in all fairness to crane manufacturers and suppliers, overheating should not be an issue.

 

[MintJulep]

To add a fan:

Buy fan and motor.

Figure out where and how to mount.

Fabricate mounting.

Run power.

Figure out how to control power.

Buy starter, control relays and enclosure.

Figure out where and how to install starter, control relays and enclosure.

Run wiring to fan.

To install a properly rated motor:

Buy proper motor.

Install.

 

[CREF]

This is P&H crane that was new in 1991 when it was installed.

Like I said above we are using it more than the rated duty cycle and the building is probably a lot warmer than it was designed for, just enough that we are tripping the motor on overheat. This is not a new problem, just an annoying intermittent problem when using the crane a lot when weather is hot.

Sounds like the answer is a fan, which is normally an easy fix (as MintJulep indicated) but we don't have much space and environment is dirty. Other fans in that area tend to quickly get caked with dust. Of course a properly rated motor would also work but was hoping not to spend that kind of $.

Was hoping for some alternative easy fix. I guess if there was one I would have known about it.

Thanks

 

[EdStainless]

Does your crane have good soft start? That might help reduce the heating a lot.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[MikeHalloran]

These guys make soft starts and VS drives that are _intended_ for crane service:

http://www.peinfo.com/

Mike Halloran
Pembroke Pines, FL, USA

 

[chicopee]

We had a lot of P&H overhead cranes and tripping of the fuse from overheating were never an issue. Research the crane model and serial numbers and ascertain that the trolley with its hoisting motor is the correct one.