Speed Control

Hi Dear,
Happy new year.
I have one gearbox which have four clutch which four different gear ratio. I want to use a simple gearbox with VFD. My question is Any VFD can provide this function?without PLC. I know different drive have constant speed mode but i need different speed ratio with main speed.
Best regards,

roxtech said:

Hi Dear,
Happy new year.
I have one gearbox which have four clutch which four different gear ratio. I want to use a simple gearbox with VFD. My question is Any VFD can provide this function?without PLC. I know different drive have constant speed mode but i need different speed ratio with main speed.
Best regards,

Click to expand...

Maybe this will help -

http://www.automation-talk.info/2011/01/how-to-run-variable-frequency-drive-in.html

moggie said:

Maybe this will help -

http://www.automation-talk.info/2011/01/how-to-run-variable-frequency-drive-in.html

Click to expand...

Dear Moogie,
I think i did not enplane my problem. I want to replace multi ratio output gearbox with simple gear box. My gear box is already connected with VFD but its output ratio change with four clutches in side the gearbox. with any combination of clutch gearbox output speed ratio change. for example when gear 1 engage i can control speed between 0-300 and when gear 2 engage. the speed can be control 0-500 and so on. Multifunction speed/constant speed did not give this function. I read function Electronic gear lock in some drives but i did not understand it.
Best regards

If you replace the 4 speed gearbox, then you will have infinitely variable speed control.

I don't understand why you would want to emulate the presence of the old gearbox once you have gotten rid of it. What is gained by doing that?

I am going to say the answer is no. A gearbox multiplies torque. That cannot be done with a drive. You would have to size your motor and drive to meet the torque required for your highest gear ratio, then hope you can overspeed enough to get the speed you need out of the lowest ratio.

Or, to state Highland Controls good advice another way, you need to design your new system, not by what the old system could supply, but by what the load requires. That would include load speed range and required torque over that range.

That way, you avoid duplicating any errors or overdesign in the old system.