CA7 Contactors



Technical Tips & FAQs

Using an Interposing Relay with a CA6 Electronic Coil Contactor

QUESTION: Can an interposing relay be used in conjunction with a CA6-__-EI electronic coil used in the ‘–EI-‘ mode?

ANSWER: We do not recommend the use of an interposing relay with any of the CA6-__-EI contactors with electronic coils. The CA6-__-EI contactors with electronic coils were specifically designed to be actuated directly from a low voltage low current PLC output.

The CA6-__-EI contactors with electronic coils draw a large amount of inrush current during start up when using an interposing relay to energize A1 coil terminal (assuming you are NOT using the PLC interface). During the inrush time, the coil will draw 40 amps for 1 millisecond, and 20 amps over a 20 millisecond time period. The total inrush time period is about 80 milliseconds before the contactor coil draws its sealed current.

EXAMPLE: We recommend wiring a CA6-180-EI-11-24D DC contactor for PLC control. The signal required is 24V DC, 15 mA max. If you must use an interposing relay, use the CA6-180-L22-24D contactor which uses a conventional DC coil. Inrush is 540 watts (22 amps of inrush). The interposing relay would have to be a CA7-30E-10-24E contactor or larger.

September 2017

Jason McCoy

Jason McCoy, Product Manager

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