Bucket elevator drawing high power

oriehi

A bucket elevator for conveying solid material (cement mill feed of 30mm~2.5mm) draws an abnormally high current when loaded. some buckets where discovered deformed. The deformed buckets where changed, but the elevator still took high kilowatt on start up. Please what could be the cause.

Simon Bridge

Welcome to PF;
Lots of things could be doing that - maybe the motor is a bit broken?

It's not clear why you'd expect a deformed bucket to change the load on the motor.
Is the higher than spec current drawn only at the startup, and then it settles down, or is it like that all the time it's running? (Or very high at startup but also higher than spec while running?)

oriehi

The bucket normally draws high load on start up, but stabilizes in few seconds on normal operations with no load (ie about 12kw). but when loaded, the power drawn goes as high as 120kw, as against about 80kw, on normal operating conditions.
We suspected restrictions, but on inspection no restriction was discovered.

tygerdawg

Some thoughts:

• motor bearing damage or failure
• motor winding damage or failure from overheating
• gearbox bearing damage or failure
• gearbox lubrication failure
• bent or damage chain links
• carrier shaft bearing damage or failure
• bent or damaged carrier shafts
• material change (is heavier per unit volume)

The increased current you get is due to an increased load. It could be an increase in torque from many causes.

Simon Bridge

Yeah, that's how I was imagining things ... and I also imagine that something gumming up the works is the most common cause for unusually high loading on the motor.

In the absence of external mechanical drag, you have to suspect the motor is wearing out.
What tygerdawg said ... you just have to work through a checklist.

oriehi

Thanks alot guys, we'll check it out