Variable resistor with programmable set points?

[Moneil]

We have a carousel that we use to replicate filling lines at beverage plants. Basically it is a 2 foot diameter wheel that holds (14) 20 ounce bottles and rotates at high speeds. We are running tests at high speed ramp up, going from 0 containers per minute to 1,200 cpm in about .75 seconds. The problem is that our carousel speeds up very very quickly at first and then settles out. We would like it to ramp up at about 1 cpm per ms. Basically 0-1,000 cpm in one second. Our carousel is controlled via some sort of variable resistance module that has a dimmer type switch. Is there any product that we can get that would do the following:

I want to measure the voltage and current going to the motor for the carousel at given line speeds. So I would set our resitor to a point that will give us a line speed we want and then take a reading. Basically take a reading at every 100 cpm from 0 to 1200. I was hoping that there was some sort of variable resistor that I could program the current/voltage set points into. Then basically have it use those as a linear reference and ramp up through them in a given time interval. So it would give our carousel the 10 set points over the time period we
want so that we can get a better linear acceleration to test with.

 

[Skogsgurra]

A very basic frequency inverter will do exactly what you want.

Talk to Allen Bradley (Rockwell Automation), ABB, Siemens or any other electrical company. They have inverters from fractional HP (at a cost around USD 100) to megawatts. All of these inverters can feed ordinary induction motors and have linear ramps that can be set from zero to almost infinite acceleration times.

Your electrician surely knows about them.



Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[TurbineGen]

Gunnar is right. A frequency inverter is your best solution. They are cheap and easy to set up. If you really want to go with a variable resistor, you cuold use a saturable core reactor, but the frequency inverter is much easier.

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If it is broken, fix it. If it isn't broken, I'll soon fix that.

 

[waross]

A hint as to the type of motor would help greatly!

Bill
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"Why not the best?"
Jimmy Carter

 

[itsmoked]

We are talking about three phase motors.

I am amazed you accelerate from 0 to 1000cpm(71RPM) in so short a time. Seems like a lot of inertial to accelerate so quickly.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

Hi Keith, yes I know that all the answers were in reference to a three phase motor, but I can find no information in the original post as to what type of motor is installed.

Our carousel is controlled via some sort of variable resistance module that has a dimmer type switch.

????

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

Yes Bill.

That wasn't directed at you but to alert the Oposter that all the VFD statements,(esp Skoggs), were for 3-phase motors.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[LionelHutz]

Sounds like it might be a DC motor?

Would a servo motor not be very well suited for this?

An AC induction motor with a VFD should be capable of doing what is asked but the acceleration is very quick and with the slip of the motor the OP may still not get real linear acceleration.