Ladder logic

I want to make a ladder logic to drive a Reversable motor starter CCt for Changing rototional direction of 3phase Ac Induction motor.
Please is there any one can help me.

Nadir Mahgoub
Sudan
Tel 00249 9 18281000
[email protected]

It's all in the INFO! ! !

Anymore info? Help us to help you!

We have a Heenan coupling style motor on site, quite large 15+kw (???)The ac motor runs in one direction when winding one type of board and is reversed when winding another type. The motor takes up to 10 minutes to stop turning before it can have its D.O.R altered, as you can imagine!

So please offer more details.

What conditions are required for forward and reverse?
What PLC are you using, although not detrimental?
Have you any I/O available?
Have you access to the PLC?
What application is it for?

Use Inverter

nader
You don't need a PLC for this job.All what you need is a variable speed drive(inverter) you can reverse the direction of rotation for your motor through it either using the local buttons in the front of the inverter or by wiring switches to the control terminals
BR

You don't need a PLC for this job.All what you need is a variable speed drive(inverter) you can reverse the direction of rotation for your motor through it either using the local buttons in the front of the inverter or by wiring switches to the control terminals

Click to expand...

I wouldn't be so sure about not needing the PLC. As stated by Silva
a large motor requires sufficient time to come to a standstill after
the windings have been de-energized.
You can reverse the motor direction immediatelly after de-energizing the windings but you may face mechanical problems based on repeated mechanical over stressing as well as blowing of the fuses (unless you oversize them).
Depending on the inertia of the motor and load that has to be moved in the opposite direction you will want to introduce a delay.
This may not be an issue with smaller and or lightly loaded motors.
I personally always provide some sort of delay before changing the direction just to be on the safe side. If you need a very fast
change in the direction of rotation you may want to consider using an AC servo motor. Emerson electric / Control Techniques is the
leader in this field.

You can also use a DC motor and a regen drive to absorb the kinetic energy. I am not sure that AC drives are regenerative?
I once used an AB 1336 plus drive and a load resistor on a plating hoist application. The resistor was supposed to absorb the energy and
bring the motor to a quick stop. It was lighting up like a christmas tree. The resistor eventually burned itself out.

The PLC system i am using is S7-200 siemens.
and i want to drive this motor in both direction.(FWR and Backward).
there is no input and output.

Thanks for all..

Nadir Mahgoub

nadirmhh said:

there is no input and output.

Click to expand...

OK, Nadir, I think you need to get some assistance here. If there are no inputs and no outputs you essentially have an industrial grade doorstop. Inputs and outputs are how the PLC monitors and controls its little section of the world.

A reversible motor starter itself is a common off the shelf item and inherently needs no external logic to perform it's basic function.

I think you are in a little over your head. I strongly suggest you get some assistance from an experienced engineer/technician/electrician, or else you need to provide a lot more details of your problem.

WOW

TOM YOU SOOOO CRUEL SOMETIMES!!

Is the PLC actually out of its packaging yet?
Is the PLC intended for use in just controlling a motor's direction?
Does this PLC and motor already exist in a system?

What are you actually hoping to see as a solution because I aint got a clue what the actual problem is that you have!! banghead

I hope you are not going to ask where you can get FREE software and cables to program your PLC?

I have just finished a 12 hour shift after 20 days holiday and my team are playing ****e in a live FA Cup game. mddr