Before you call an electrician about a tripping motor or drive

Published October 1, 2026 · Vili Power Solutions

What to record

These are all observations you can make safely from the operator side of the equipment.

• The fault code or trip indication. Write down exactly what the drive display, the PLC screen, or the starter shows, before anyone resets it. On a drive, the fault history may hold the last several faults. A photo of the display works.
• Which device tripped. A drive fault, an overload relay, a breaker, and a fuse each point to different causes. Note which one it was if you can see it without opening anything.
• When it trips. At start, while running, while stopping, at a certain speed, at a certain time of day, or after a certain amount of run time.
• What the load was doing. Full hopper, heavy product, cold startup, a pump against a closed valve, a conveyor loaded more than usual.
• Heat. Is the room hot? Is the drive or motor much hotter than usual to the touch on the outside? Are cooling fans running? Is a filter visibly clogged?
• Dust and moisture. Buildup on the motor, on filters, or on the outside of the enclosure, and any sign of water around the equipment.
• Noise, smell, and vibration. Grinding, squealing, humming without turning, a burning smell, or new vibration.
• Recent changes. New equipment on the same circuit, a drive replacement, a parameter change, a motor rebuild, weather, a storm, or utility work on the line.
• Nameplate data. Photos of the motor nameplate and the drive or starter label. They tell the electrician what parts and settings to expect.
• Other equipment. Did lights flicker, or did other motors or drives trip at the same time? That points toward incoming power instead of the one machine.

Keep a simple log with the date, time, fault, and what was happening. A pattern over several trips is often more useful than any single reading.

What not to do

• Do not keep resetting it. An overload or a drive fault is protecting the motor. Repeated resets on a motor that is overheating or a cable that is breaking down turn a repair into a replacement, and can start a fire. One reset after the equipment has cooled is reasonable. Repeated trips need diagnosis.
• Do not bypass or turn up overloads. Raising an overload setting above the motor nameplate, jumping out a protective device, or installing a larger fuse or breaker removes the protection that keeps the motor and wiring from burning up.
• Do not open energized enclosures. Drives, starters, and MCC buckets carry hazards that are not obvious, including stored energy in drive capacitors and arc flash. Opening them is for qualified people working under lockout/tagout.
• Do not change drive parameters by guessing. Changing acceleration, current limits, or fault settings without knowing the cause can hide the problem until it causes damage. If someone does change a setting, write down the old value.
• Do not swap parts at random. Replacing a drive or motor without finding the cause often means the new one fails the same way.

What the electrician will check

With your notes in hand, a qualified electrician will usually work through:

• Fault history and settings. Drive fault logs, overload settings compared to the nameplate, and drive parameters compared to the motor and load.
• Incoming power. Voltage on each phase, voltage imbalance, and signs of sags or surges. A lost phase or a bad utility connection can trip several machines.
• Current draw. Current on each phase while running, compared to the motor's full load rating. High current points to the load or the motor. Unbalanced current points to the supply, the connections, or the motor windings.
• Connections. Loose or overheated terminals in the starter, the drive, the disconnect, and the motor junction box. Thermal imaging helps find hot connections while equipment is running.
• Motor and cable insulation. An insulation resistance test on the motor and the cable between the drive and the motor, with the equipment locked out and the drive disconnected from the circuit being tested.
• Cooling. Drive fans, heat sinks, enclosure filters and ventilation, and the room temperature.
• The mechanical side. Bearings, couplings, belts, and the driven equipment. A bound conveyor or a failing pump bearing trips the motor just as surely as an electrical fault.
• Grounding. Ground faults and poor grounding show up as nuisance trips, especially on drives.

From there you should get a clear explanation of what failed, why, and what it will take to keep it from happening again. For drives, see our VFD installation and repair page. For starters, buckets, and overloads, see motor control center services.

When to call

Call when a motor or drive trips more than once, when it trips along with other equipment, or right away if you see smoke, smell burning, or hear arcing. We take troubleshooting calls from plants, dairies, and commercial facilities across Northern Colorado, including Loveland and Fort Collins. Contact us or call (970) 685-2068, and have your notes and nameplate photos ready.