Page top

Lead Contents

FAQ03676 of General Purpose Relays FAQ

FAQ No. FAQ03676

Primary Contents

Question

What is coil surge?

Answer



It is a characteristic of the coil in which a large reverse voltage is momentarily generated when Relays are turned OFF. To deal with this problem, some Relays are equipped with surge-absorbing circuits.

When contacts are used for input, surge-absorbing circuits can be used to extend the service life of Relays, prevent the effects of noise, and minimize the production of carbides and nitric acid caused by arcing.

When semi-conductors, such as transistors, are used for input, reverse voltage is generated and may cause Relays to breakdown.
In most cases it is good to install a surge-absorbing circuit.

Some relays have a built-in surge-absorbing diode (for DC coils). These diodes can also be externally installed.

Comparison of Coil Surges in a 24-VDC Circuit

Comparison of Coil Surges in a 200-VAC Circuit

Recommended Products

MY

Best-selling, general-purpose relays that can be selected based on operating environment and application

LY

Power-switching Compact General-purpose Relays

G3PE (Three-phase)

Compact, Slim-profile SSRs with Heat Sinks. Solid State Contactors for Three-phase Heaters Reduced Installation Work with DIN Track Mounting.

Other General Purpose Relays FAQ