low hp 3-phase motor application

[confused859]

Please forgive me for asking perhaps stupid questions, I'm very new to this field.

I have an application that is going to use a 1HP 3-phase gearmotor and a 1/4HP 3-phase gearmotor. Each will be using a variable speed drive, such as GE's D7212 or a GS1 series drive from Automation Direct. I plan on using an external switch wired into each drive to control forward-stop-reverse.

I also plan on having a main power switch for the machine and an emergency stop switch. Do I need to use any additional components such as motor starters? When using an emergency stop, is it wired into the motor drive or is it wired into the main power coming into the machine? How do you design/wire the system such that the motors will not start when the emergency stop is reset?

Thank you four your help.

 

[2571]

first, There's no such thing as a stupid questions.
second from your questions I'm assuming you are around other equipment that may have these types of set-ups. Could you maybe pull your questions from these other machines and drawings.
I can offer suggestion but it's tough with the variables you have listed. I can help in any way possiable, I am also new to the feild and I have resulted on many occasions to looking at previous work and having to determine what was right or wrong.

Stop (e stops) at typically wired in to the motor control circuit or motor contactor as a normally closed. then the start button has a set of sealing contact that close when energizing when the contactor coil pulls in, most contactor have auxiliary contact built in. when you push the e-stop the coil is de-energized and the sealing contacts drop out not allowing the equipment be started until the start is pressed agian. I can provide a sketch if you'd like. Where do I send it.

2571

 

[CJCPE]

Variable frequency drives are designed for direct connection to the motor without a motor starter. The VFD provides the motor control and protection functions. In some situations, you want to put a non-fused disconnect switch between the VFD and motor. NEC requires a disconnect means in sight of the motor location and the driven machinery location. A motor disconnect will probably not be necessary if the disconnecting means for the VFD has suitable locking provisions.

The emergency stop can probably be connected to the VFD. However, if that is done, the motor is electronically shut off but not physically disconnected. For a physically disconnecting emergency stop, use a power contactor to control the input power to the VFD and connect the emergency stop switch to that. The contactor can also be put between the VFD and motor, but it would need to be interlocked with the VFD.

Most VFDs can be set up so that they will not restart when emergency stop is reset. You may need to use momentary contact closure forward and reverse buttons and a momentary contact opening stop button. (See above by 2571)

You should probably download the VFD manuals for the proposed drives and review the installation requirements and control features.