motor starters

[lgalla]

Hi everyone,I never see any posts of motor starters.Every piece of machinery in the shop has motor starters as required by code.As i understand in the event of a power failure or blackout a relay or magnetic contactor will disconnect the line from the motor.Imagine a power outage while running a machine.Without the starter when the power resumes your machine powers up again.When is a starter required?They are expensive at least in my shop which has 575V3 phase.
Larry

[Al_The_Man]

Starters also known as Contactors are required as a hardware disconnect on all motorized machinery.
They range from ordinary single contact to specialized ones like reversers and Definate-purpose style (Air conditioners and welders/ plasma etc).
The DIN style are now popular due to their smaller size than the NEMA counter part.
They are pricey, A good source is Ebay.
The overload trip is the optional module that fits on the output side of the contactor.
Sized according to the motor.
Another similar device is a safety relay as a E-stop device, I believe it is mandatory in most of Europe and N.America is presently coming on board.
Al.

[lgalla]

Thanks Al.
In the case of us home builders are starters necessary?If so is one main starter used or is it just necessary for the spindle.Servo and stepper drives seem to have their own protection built in.Is that enough to meet code.
Have a good beer Al
Larry Edit
Sorry should read Have a good year

[Al_The_Man]

Usually either a contactor ahead of a VFD or a heavy duty relay for a Universal motor spindle is needed.
I usually use one for a E_stop relay or though these are the slightly smaller ones known as control relays, they often resemble contactors, these can cut the power to servo/stepper supplies etc in E-stop.
Al.