|Contact Data Tables||NEMA Ratings and Test Values||Surge Suppression Information||Solid-State Relay Glossary|
NEMA Ratings and Test Values for AC Control Circuit Contacts at 50 or 60 Hz
|Maximum Current [A]|
|NEMA Contact Rating Designation||Thermal Continuous Test Current [A]||120V||240V||480V||600V||VA|
NEMA Ratings and Test Values for DC Control Circuit Contacts
|Maximum Current [A]|
|NEMA Contact Rating Designation||Thermal Continuous Test Current [A]||5…28V||125V||250V||301…600V||Make or Break at 300V or less [VA]|
Solid-State Relays Data Tables
⋆ Requires a heak sink to reach maximum current value.
NEMA Definitions for Contact Arrangements
Form A Contacts
A Form A contact arrangement is one that has single-pole, single-throw, normally open contacts. The function of this arrangement is to close a circuit when actuated.
Form B Contacts
A Form B contact arrangement is one that has single-pole, single-throw, normally closed contacts. The function of this arrangement is to open a circuit when actuated.
Form C Contacts
A Form C contact arrangement is one that has single-pole, double-throw contacts with three terminals - one for normally open, one for normally closed, and one common. The function of this arrangement is to transfer a circuit when actuated.
Form X Contacts
A Form X contact arrangement is one which has single-pole, single-throw, normally open double-make contacts. The function of this arrangement is to close a circuit when actuated.
Form Y Contacts
A Form Y contact arrangement is one that has single-pole single-throw normally closed double-break contacts. The function of this arrangement is to open a circuit when actuated.
Form Z Contacts
A Form Z contact arrangement is one that has single-pole, double-throw, contacts with four terminals — two for normally open and two for normally closed. The function of this arrangement is to open one circuit and close the other.
Repeat Cycle or (Flicker)
Power is applied continuously. When a start signal is applied, the timing cycle begins. When the time delay is completed, the output contacts change state and the next timing cycle begins. This cycle will repeat until a reset signal is applied or power is removed.
Mounting — Timing relays are available in several different models. They can be plugged into the same socket as the relay, or use a separate plug-in socket mounting.
Contacts — The contacts are of various types and ratings. Refer to the appropriate specification pages for more details.
Functionality — Timing relays with multi-range and multi-function capability are available. This allows you to stock one relay to cover a wide variety of applications.
External Trigger Switch — OFF-Delay, One-Shot, and other timer functions require an external trigger switch (from a relay or push button) to control the timing function. The external trigger switch will cause the timing function to start. In OFF-Delay, the trigger switch closes to energize the output and when the trigger switch opens the OFF-Delay starts to time out. At the end of the time delay, the output is de-energized and the output contacts return to their shelf state.