Jogging

Run a motor in short controlled bursts for positioning — by deliberately defeating the seal-in so it stops the instant you let go.

What jogging is

Jogging (or inching) means running a motor in short bursts — it runs only while you hold the jog button and stops the instant you release. No seal-in, no latching. You use it to nudge a machine into position: line up a coupling, index a conveyor, thread material into a machine.

The key difference from Start/Stop

A normal start/stop circuit wants to seal in and keep running. A jog circuit must do the opposite — it must defeat the seal-in so the motor drops the moment you let go. That is the design challenge: energize the contactor without letting the holding contact latch.

How it is done

The classic method uses a jog button with both a NO and an NC contact block (the two-block button). When you press JOG:

• The NO block closes and energizes the contactor — the motor runs.
• The NC block simultaneously opens the seal-in path — so the holding contact has nowhere to latch.

Result: the motor runs only while you hold JOG. Release it, the NO block opens, the coil drops, and because the seal-in was disabled the whole time, nothing keeps it running.

Safety note

Jogging cycles a motor and contactor hard — repeated inrush, lots of contactor wear. It is for brief positioning, not for running a process by tapping. And because the motor moves while someone is often close to the machine, treat jog circuits with the same respect as any live-motion control.

What to take away

Jogging runs a motor only while held, by energizing the contactor while simultaneously disabling the seal-in. The two-block jog button (NO closes the run path, NC opens the holding path) is the standard way.