Industrial Engineer · phase 13 of 16 · noun

Bypass

Power and control arrangement that allows a motor to operate across the line when the drive is isolated or unavailable.

The Explain card

Plain English: A bypass is a power and control arrangement that lets the motor run straight across the line when the drive is out of service. Contactors isolate the drive and connect the motor to the supply, at full speed only.
Example: A hospital's air handler has a drive with a bypass. The drive fails at midnight, the bypass is switched in, and the fan runs at full speed until a replacement drive arrives.
Why it matters: Bypass buys availability for critical fans and pumps, and it needs its own overload, interlocks and a way to keep both paths from closing at once. In bypass the motor starts across the line, so the load and the supply have to be able to take that.
Hook: A way to run without the drive, at one speed.

How the word is built, where it came from, and what it sits beside in memory.

In a sentence

The technician verified the contactor interlocks before placing the motor starter in Bypass.

How it is built

Where it came from

Origin: an American English compound formed from by and pass
Entered the language: 1848
What changed: It first described a route around an obstruction, then broadened to alternate paths around equipment or processes.

How it is spelled

Pattern: It is a closed compound whose two base words retain their spellings.
Pattern: The pass element keeps its final double s.

Spelled like

Broken into chunks

What it sits beside

Same subject

Same shape

closed compounds beginning with by

electrical operating modes

Phase 13: VFD Power Quality, Wiring, and Motor Protection

Harmonics, reflected waves, shielded cable and bearing currents: the side effects a drive inflicts on everything around it.