Inverter drive on 3ph S/C
Inverter drive on 3ph S/C
(OP)
Hello,
I have recently come across a situation involving a 3ph s/c induction motor, controlled by an Inverter drive, the motor is 415/240v 50Hz coupled to a gearbox, but the inverter has been set up to run at 60hz when upto full speed.
Now its been a long time since I have done any calculations of this nature so I would like a little help please.
Firstly from what I can remember it is not good for the life of the motor to run it at high hz, secondly assuming the loading was calculated correctly when installed will it actually run any faster? or if the hz was increased any more what effect would it have?
Basically its required that the gearbox output rotation speed is increased. I believe the easiest way would be to change the gearbox ratio, assuming the motor & inverter can accomodate this, but I would like a second opinion and some calculations to back up my view. Thanks
I have recently come across a situation involving a 3ph s/c induction motor, controlled by an Inverter drive, the motor is 415/240v 50Hz coupled to a gearbox, but the inverter has been set up to run at 60hz when upto full speed.
Now its been a long time since I have done any calculations of this nature so I would like a little help please.
Firstly from what I can remember it is not good for the life of the motor to run it at high hz, secondly assuming the loading was calculated correctly when installed will it actually run any faster? or if the hz was increased any more what effect would it have?
Basically its required that the gearbox output rotation speed is increased. I believe the easiest way would be to change the gearbox ratio, assuming the motor & inverter can accomodate this, but I would like a second opinion and some calculations to back up my view. Thanks





RE: Inverter drive on 3ph S/C
Thread237-31684 & Thread237-21451 & other threads that pretty much already cover this.
RE: Inverter drive on 3ph S/C
Similar questions need to be raised about the gearbox, increased speed/load, and lubrication.
You probably have a common package of equipment that will work, just not enough details to be specific here.
RE: Inverter drive on 3ph S/C
RE: Inverter drive on 3ph S/C
Bobby69
RE: Inverter drive on 3ph S/C
An example that I have encountered in the past is setting the base frequecy for 120Hz on a 460 V network so that a 230V motor could be used on the 460 network without rewinding.
While doubtful that this is the case here it does illustrate that one should not go monkeying about with drive parameters unless you are sure why you are doing so...
Using the VFD it is possible to overspeed (hesitate before going more than 50% overspeed) the motor. As pointed out above this will result in a drop in torue but since RPM has increased the output HP remains the same. I suspect though that you will take a hit on eff. but others here can better adress that issue.
RE: Inverter drive on 3ph S/C
RE: Inverter drive on 3ph S/C
RE: Inverter drive on 3ph S/C
RE: Inverter drive on 3ph S/C
http://www.anorad.com/applicationAnalysis/competitiveAnalysis.htm
for "anti Eddy Current design" at linear motors:
Velocity - Linear motors are capable of very high velocity in excess of 10 m/s. Anorad’s proprietary anti eddy current design assures negligible eddy current losses at high speeds.
RE: Inverter drive on 3ph S/C
http://www.esmagazine.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2503,13058,00.html
(for "output waveform effects")
http://www.theaustin.com/html/ra-variable-frequency_drives.html
At higher frequencies, they lead to eddy currents and skin-effect losses that produce no usable work, but do produce heat, which must be dissipated.
RE: Inverter drive on 3ph S/C
RE: Inverter drive on 3ph S/C
http://www.lincolnmotors.com/
http://www.lincolnmotors.com/pdf/E70.pdf
that removes heat at low motor RPMs.
RE: Inverter drive on 3ph S/C
Visit
http://www.sea.siemens.com/drivesbu/support/catvc/sec4b.pdf
for more info
RE: Inverter drive on 3ph S/C