Wye-Delta Starter 2

[reggie]

I need to supply wye-delta motor starters for equipment going to Europe. I was shocked by the pricing I received on the units. I thought these where not much more than a standard motor starter with an additional contactor and some timing hardware. Can these be made from individual components?

 

[senglish]

You're right. A star-delta (Y-delta) starter has two contactors, interlocked via their auxiliary contacts so that only one can be closed at any time, with a timer to switch from star to delta a fixed time after the motor has been started. You could make one from individual components.

Maybe you should check that you are comparing like with like. Does the starter you've been quoted a price on have extra protective relays (underload as well as overload, electronic protection, motor seal leak or oil in water detection, etc)? Will it be constructed to the same standards as the DOL starter you're comparing with (panel construction and compartment segregation, Ex-rated, some kind of additional mechanical interlocking mechanism between the two contactors)? Does it have extra controls (lamps, pushbuttons, remote comms)?

Maybe the price hike is partly because of the extra cabling requirements to the motor (6 cores instead of 3)?

Can't think of any other possibilities at the moment.... have you gone to more than one manufacturer for a quotation?

 

[reggie]

Yes, I've wemt to Siemens and AB. I just got a revised quote from AB that was much more in line with what I would expect to pay. It was less than half the price of the original quote. I reviewed all the specs to ensure the comparisons were equal and they are.

Thanks for the feedback.

 

[jbartos]

Suggestion: The Delta-Y starter can be implemented by two or three contactors depending on the transitions that are required or specified. This may need certain amount of caution. Also, the proper time setting between the y-operation and delta-operation start is needed. Square D catalog includes both schematics at

http://www.squared.com

 

[rhatcher]

A few follow-up comments on this topic:

- these are known as wye-delta (y-delta) based on the order of operations (wye start, delta run)

- minimum of three contactors required (open transition starter): main, start, and run. Four starters are used for a closed transition starter. They clearly show three contactors for the open transition model, 1M, 1S, and 2M. These would be known as main, start, and run respectively. The closed transition model has a fourth contactor 2S.