TL;DR

Overheating with high current is usually mechanical overload or supply phase imbalance. Measure phase currents, check the load, and verify supply voltage balance is within 1%.

What you might see

motor housing above 85°C
overload relay trips repeatedly
current above nameplate FLA
burnt smell near the motor
uneven phase currents

Likely causes

Tap to mark as ruled out

Mechanical overload, stuck or jammed driven equipment, bearing failure on the load side
Phase imbalance greater than 1% causing one winding to carry disproportionate current
Single-phasing from a blown fuse or open contactor pole
Plugged motor cooling fins or intake screen reducing airflow

Required tools

Clamp ammeter (true-RMS)
Multimeter rated for the supply voltage
LOTO kit
Cleaning brush

Safety first

All voltage measurements on energized equipment require category-rated PPE and an Energized Electrical Work Permit.
Do not run a motor that is tripping repeatedly, investigate first to avoid winding damage.

Procedure

7 steps · ~30 min

1
Lock out the motor disconnect and verify zero voltage with a meter.
2
Inspect the driven equipment for obvious mechanical resistance, turn the load by hand if possible and check for binding.
3
Restore power and measure phase currents at L1, L2, L3 with a clamp ammeter under normal load.[1]
4
Compare each reading to the Full Load Amps (FLA) on the Baldor nameplate. Sustained current above 115% of FLA is an overload condition.[1]
5
Measure phase voltages L1-L2, L2-L3, L1-L3. Calculate the percent imbalance, should be at or below 1% per NEMA MG-1.
6
If imbalance exceeds 1%, work upstream, check for loose connections at the contactor, blown fuses, an open contactor pole, or a sagging supply transformer.
Warning: Voltage measurements on energized equipment require an Energized Electrical Work Permit and appropriate PPE.
7
Inspect the motor cooling fins, intake screen, and end-bell vents for debris or paint buildup. Clean with a brush; do not use compressed air directly into the windings.

Sources

Baldor Reliance Industrial Motor Maintenance Manual, Baldor Electric Company (ABB)
Baldor Industrial Motor Maintenance Manual, full-load current and voltage balance specifications (general)
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