Replacing 30 kw motor with 60 kw motor in plate bending m/c
Replacing 30 kw motor with 60 kw motor in plate bending m/c
(OP)
A 30kw motor that was supplied along with the original 70mm
plate bending m/c has burnt out.Right now we only have a 60 kw motor as a replacement. Both are slip ring 975 rpm motors.Assuming that the factor of safety on various mechanical components like gears ,shafts etc used in the m/c is 1.5 for static strength,does any one forsee any possible damage that is likely to be caused to gear box,rolls etc by this replacement .Use of m/c is infrequent (say once in a month).
plate bending m/c has burnt out.Right now we only have a 60 kw motor as a replacement. Both are slip ring 975 rpm motors.Assuming that the factor of safety on various mechanical components like gears ,shafts etc used in the m/c is 1.5 for static strength,does any one forsee any possible damage that is likely to be caused to gear box,rolls etc by this replacement .Use of m/c is infrequent (say once in a month).





RE: Replacing 30 kw motor with 60 kw motor in plate bending m/c
Motors "Burn out" when they are asked to more than they are designed for. Frequently this happens when something in the output train jams, causing the motor to stop turning. In such a condition, the motor will produce its maximum torque before it burns.
So if you replace the motor with one with twice the power, it is very likely that you will find the next weakest link.
RE: Replacing 30 kw motor with 60 kw motor in plate bending m/c
1.5 for static strength.Load in both cases is same and corresponds to 30kw rating at 975 rpm.
RE: Replacing 30 kw motor with 60 kw motor in plate bending m/c
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Sometimes I wake up Grumpy.
Other times I just let her sleep!
RE: Replacing 30 kw motor with 60 kw motor in plate bending m/c
RE: Replacing 30 kw motor with 60 kw motor in plate bending m/c
The running speed will be slightly higher.However since pullout torque(the max the motor exerts during startup,though only for may be a second)is generally about 2.75-3 times the rated torque,60 kw motor will exert so much more torque during startup.Please comment on this difference in torque during startup.I don't really know if pull out torque explicitly determines the design of gears, shafts etc .In various books its the full load torque which is mentioned for static strength design.
RE: Replacing 30 kw motor with 60 kw motor in plate bending m/c
The only thing to worry about is locked-rotor torque. In that case the larger motor will max out at the higher torque and the mechanism will have to be able to handle it.
Have you considered a simple torque-limiter at the shaft coupling?
Don
Kansas City
RE: Replacing 30 kw motor with 60 kw motor in plate bending m/c
The larger motor will also deliver more accelerating torque than the smaller one so the machine will reach speed faster. Without knowing much more about the machine it is difficult to say what the consequence of this might be. You might consider a soft start to control the acceleration if you think this could be a problem. Drop a post in forum237: Electric motors & motor controls engineering if you need advice on that - there a couple of guys who specialise in soft starters.
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Sometimes I wake up Grumpy.
Other times I just let her sleep!
RE: Replacing 30 kw motor with 60 kw motor in plate bending m/c
which must be remedied before motor replacement.