VVVF Drive

What part of the math do you not understand? 2200 is greater than 750!

You cannot run a 2.2kW motor from a .75 kW drive!

As to your other question, you can theoretically control any size motor from a larger drive. But in most cases the programming parameters will not allow you to run and protect a motor that is less than some specific size, and that size varies by model, even within a given manufacturer. So the only people who can answer that question for you are Siemens, and even they will need to know the exact model number.

Dear sir,

Thanks for your comments.

Hi,

It will be difficult to run a 2.2kw motor on a 0.75kw drive. If the ratings were close, say, VSD of 0.75kw and motor of 1kw, then there are ways of running the load and this also depends on the type of VSD you have. The Vector control types would be the best for this as you can play around with some parameters and 'force' the drive to run the load.

Siemens drives - and I want to believe others too - have a 150% overload capability for 60secs, so if push came to shove, you could force the drive to start the bigger motor BUT the load on the motor should be within the drive rating.

On your 2nd question, you can run several motors on 1 drive but the total motor ratings should not exceed the drive rating. You can run these on a uniform control basis, start-stop-speed-rotation is the same for all motors. Alternatively, if you want to cascade the start-stop-speed of the motors to suit a paticular sequence or individual values, you need to add some cards on to the drive control card, e.g. a ProfiBus card, maybe a Pulse Encoder module unit depending on your application. You would need to assign bus-addresses to each motor for selective control over the ProfiBus.

Let me know if you need some more info' and do have a nice day.

Cheers

DEAR SIR VERY THANKS FOR YOUR SUGGETION.

SIR, I WANT TO RUN A STOPPER FORWARD & BACKWARD WHEN I CALCULATE IT REQUIRE ONLY .1KW MOTOR FOR THAT BUT I PUT .5KW ,PROBLEM IS KNOW THAT THE MOTOR UNABLE TO PRODUCE THAT MUCH STARTING TORQUE TO GEAR BOX OF STOPPER WHICH HAVE 1:16 RATIO TO MOVE . NOW I HAVE A MOTOR WITH 22NM ON 750 RPM ie 1.72 KW BUT I HAVE NO DRIVE EXCEPT THE MENTION ONE I THINK THAT THE MOTOR TAKE ONLY THAT MUCH OF CURRENT WHICH IS REQUIRED TO PRODUCE THE TORQUE .I ALSO THINK THAT MOTOR TAKES CURRENT BELOW THE RATED ONE . THE MOTOR PRINTED DATA IS T= 22NM AMPS =10 V= 415 RPM = 750 S4 DUTY 50Hz

ROLLER TABLE MOTOR . PLEASE ADVISE ME . I WANT TO RUN ON TEST BASIS AFTER WE ARRANGE THE DRIVE .

THANKS & REGARDS

BHUPENDER

You can't use the 0.75kw drive with 2.2kw motor. The rating of the drive must be higher than the motor. The ideal rating of AC motor to be controlled by the AC drives is 50% of the drive, but you have to adjust the Current Limit on the program ( put the value from the motor nameplate Amps).

--Ruben Cabreros

rubencabreros@lycos.com

Philippines

I agree you cannot use a 0.75kw drive on a 2.2kw motor. However, I diagree that the ideal motor rating for an AC motor is 50% of the drive. I have designed and commissioned numerous VSD applications of various power ratings and have never come across the 50% rating.

A motor rating (or ratings) should not be more than the drive rating - this I agree.