Need help selecting a motor for a centrifugal machine

Thread Starter

BHUSHAN WANJARI

Joined Dec 21, 2017
1
hello friends

I am design centrifuge machine .
so i need some help
my machine specification 4200 rpm
so which motor suitable for that and which drive we are used also how to feed back motor speed to vfd to control and accurate speed of motor
please help me for new development
 

MaxHeadRoom

Joined Jul 18, 2013
26,248
my machine specification 4200 rpm
so which motor suitable for that and which drive we are used also how to feed back motor speed to vfd to control and accurate speed of motor
The term VFD implies an AC motor, a 3ph induction motor with a VFD and either a flux vector or encoder feed back control version, depending on how precise the control needs to be.
Under around 5HP the VFD can be fed from 1ph AC supply.
The max rpm of a 2 pole motor would be around 4500rpm using a VFD.
Max.
 

MisterBill2

Joined Jan 23, 2018
13,693
hello friends

I am design centrifuge machine .
so i need some help
my machine specification 4200 rpm
so which motor suitable for that and which drive we are used also how to feed back motor speed to vfd to control and accurate speed of motor
please help me for new development
The centrifuges that I am familiar with use a DC brush type motor and a DC drive that supplies a variable voltage at several amps. But those units also have a 6 inch flat belt pulley on the motor and a 1 inch diameter pulley for the rotor, which gives a large speed increase.
For other variable speed applications, if you want a high quality package that will work as needed when you first switch it on, buy a BALDOR brand variable speed drive. The money saved by having it do what you need as soon as you enter in the command will easily save more than the cost of the VSD system. AND, if it needs to be serviced or replaced the company can sell another or reapir that one.
 

MisterBill2

Joined Jan 23, 2018
13,693
You haven't specified what load you wish to centrifuge. Is this for micro-samples or for tons at a time?
Alec has made a very important point. The size of the load matters a lot, because in a centrifuge the torque is required mostly to overcome friction, and given the reality of bearings, the friction depends on the load. In addition there is the rate of acceleration, the quicker the load needs to speed up the more power required. So there are a lot of questions that must be answered before any respose means anything.
 
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