Contactor's Coil Current

Question

YuCo YC-CN402-24V CN-PBC402-24V DEFINITE PURPOSE CONTACTOR with a Packard PF42440 Control Transformer Class II Foot Mount 40VA 24V to activate the 2vac coil. The circuit is a 220v 20amp motor. My question is how much current draw does it take to open that 24vac coil on the contactor? Will it take all the current from the transformer to drive the coil? If it does not take all the current can you split the current out of the transformer and use it for say driving the controller (Arduino). Thank You for your help.

Answer 1

It looks like the coil needs a maximum inrush of 32VA at 60 Hz, so you have some power left over to drive a controller. The holding current is much less, so if you have a big enough filter capacitor on your Arduino power supply to last through the inrush, you can use more average power.

In the future, please provide your own links to the relevant data.

Answer 2

It depends on the power you consume on your Arduino system. The datasheet on your link shows:

The maximum likely VA is 35 @ 50 Hz and the coil will consume only 7 VA when closed.

If the Arduino is NOT controlling the contactor start....

1. If you bridge rectify the output of the Control transformer then you need to be careful of the value of any filter capacitors used.
   If the value is too high then you could cause the contactor to bounce at turn-on.
2. It may be advisable to include a series resistance after any bridge resistor to minimize inrush current for the Arduino supply, though if all you are powering is an MCU this is probably not going to be an issue.

If you are using the Arduino to turn on the contactor.....ensure your Arduino power supply has enough supply carry through to miss a couple of cycles when you turn on the Control transformer.