Motor Wont Start Troubleshooting Guide

Motor Won’t Start — Industrial Troubleshooting Field Guide

A motor that will not start is one of the most common breakdown calls in industrial maintenance. The fastest repair comes from following the circuit logically instead of guessing or replacing parts unnecessarily.

The Shepherd Manuals Motor Won’t Start — Industrial Troubleshooting Field Guide is a focused 21-page quick-reference PDF designed for industrial electricians, maintenance technicians, apprentices, mechatronics technicians, and instructors.

This guide walks the technician through a practical troubleshooting sequence beginning with the key question:

Does the contactor pull in?

From there, the problem is separated into the control circuit or the power circuit, helping the technician quickly narrow down the fault and determine the next test.

Inside the Guide

• Motor-won’t-start troubleshooting sequence
• Control circuit versus power circuit diagnosis
• NEMA/JIC-style three-wire START/STOP circuit
• START, STOP, overload, and holding-circuit troubleshooting
• Contactor coil testing
• Control-voltage tracing
• Contactor pulls in but motor does not run
• Three-phase line-side and load-side voltage checks
• Blown fuse and breaker problems
• Single-phasing
• Voltage imbalance
• Open motor leads
• Bad contactor poles
• Motor winding faults
• Mechanical load problems
• Expected meter readings
• Field troubleshooting case studies
• Technician checklist
• Measurement worksheet

Three Full-Page Troubleshooting Flowcharts

Includes large, easy-to-follow flowcharts for:

• Motor Won’t Start
• Contactor Won’t Pull In
• Contactor Pulls In but Motor Does Not Run

Each chart uses clear decision points and YES/NO paths so the technician can move through the problem quickly on the plant floor.

Built for Real Field Use

This is not a general motor-controls textbook. It is a focused troubleshooting guide built around one specific service call:

“The motor won’t start.”

The troubleshooting method follows:

SYMPTOM → TEST → EXPECTED READING → DECISION → NEXT ACTION

Use it as a quick field reference, apprenticeship training aid, maintenance-department resource, or classroom troubleshooting supplement.

Format: PDF Digital Download

Length: 21 pages

Price: $9.99

Publisher: Shepherd Manuals

Practical. Technical. Trusted.

Find the cause. Take the correct action. Get the motor running.