NEMA Timing Relays for Industrial Panel Timing Control

NEMA timing relays are used when a control circuit needs a preset delay before contacts change state. They are commonly applied in industrial automation, machine sequencing, motor control panels, auxiliary logic, and other delay relay applications where repeatable timing is required. Key selection factors typically include timing function, mounting style, contact format, timing range, and compatibility with the intended relay or socket platform.

This category focuses on Allen-Bradley NEMA timing relays for relay-based control systems, including Bulletin 700-PS solid-state timing relays and Bulletin 700-HT tube base timing relays.

Allen-Bradley Bulletin 700-PS and 700-HT Timing Relays

• Bulletin 700-PS solid-state timing relays are designed for use with compatible Bulletin 700 relay families. Rockwell specifies mounting on 4-pole Bulletin 700-P, 700-PK, 700-R, and 700-RM relays, and on 2-pole Bulletin 700-PH relays. With an adapter plate, they can also be used as standalone timers. These models offer a 0.1...120 second range and are convertible to ON-delay or OFF-delay, making them a practical choice for adding timing control within an existing NEMA relay assembly.

• Bulletin 700-HT tube base timing relays are self-contained timing relays for general purpose panel applications. They mount on tube-type bases and offer on- or off-delay options, rugged pin style socket mounting, 10 A DPDT contact ratings, fixed timing ranges from 0.1 seconds to 30 minutes, and one adjustable timing range from 0.1 seconds to 3 minutes. This style is often selected where socketed installation, maintenance access, and straightforward replacement timing relays are important.

How to Choose the Right NEMA Timer Relay

Choose 700-PS when your panel already uses a compatible Bulletin 700 relay family and you want to add timing in a compact attachment-style format.

Choose 700-HT when you need a standalone NEMA timer relay with tube-base mounting for general purpose control panels or replacement timing relay needs.

The main difference is relay-platform integration versus independent installation. A 700-PS timer supports compact panel design and relay-family compatibility, while a 700-HT timer is better suited to applications that benefit from socket mounting, serviceability, or a complete standalone timing relay format.

NEMA Timer Relay Selection Considerations

When comparing NEMA timing relays, review the required delay function, mounting method, timing range, contact arrangement, and relay or socket compatibility. For example, 700-PS models cover short adjustable delays from 0.1 to 120 seconds, while 700-HT models include fixed ranges up to 30 minutes plus an adjustable option to 3 minutes.

It is also helpful to consider panel layout, wiring approach, maintenance preferences, and whether the application calls for a timing attachment or a complete replacement timer relay. For many buyers, the decision comes down to whether the panel is built around a compatible Bulletin 700 relay platform or whether a tube base timing relay is the better fit for standalone timing control.