What is an HFA relay?

What is an HFA relay?

The type HFA relay is designed for applications where a number of auxiliary functions must be performed simultaneously. Six contacts are provided. If more than six circuits are to be controlled, the coils of two or more relays may be connected in series (DC only) or in parallel.

What is role of mechanical contact A and auxiliary relay?

Functions of Auxiliary contacts or switch in relay: The relay contact does complete the trip circuit but it can not disconnect this. As the relay contact is so light and weak mechanically to act fast. The disconnecting of trip circuit is done by auxiliary switch or contact.

How do you test an auxiliary relay?

Testing Procedures

1. Measure Relay Pick up & Drop off Voltage/current.
2. Measure Relay Pick up & Drop off Timing.
3. Measure Relay Burden.
4. Measure Relay Contact Resistance.

What is no NC and common in relay?

The COM (Common) connection of a relay is the part of the relay that moves. When a relay is off, the COMMON is connected to the NC (Normally Closed). The NO (Normally Open) connection of the relay is not connected until the relay turns on. It is possible to use Two relays to create a Normally Closed condition.

Do relays have auxiliary contacts?

The auxiliary contact is often used in a relay logic circuit, or for some other part of the motor control scheme, typically switching 120 Volt AC power instead of the motor voltage. One contactor may have several auxiliary contacts, either normally-open or normally-closed if required.

Can one relay coil control several different relay contacts?

An electromechanical relay will usually have only one coil but may have any number of different contacts. Normally closed contacts are contacts that are closed when the coil is de-energized and open when the coil is energized. You just studied 53 terms!