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Motor Wiring Lead and Rotation Chart

Lead colors commonly found on PSC blower and fan motors, the standard NEMA lead markings, and how rotation is reversed. The motor's own label governs every connection.

Ref HV-0057NEMA MG 1

Draft, open for review. Check every value against the governing standard and the manufacturer’s data before use.

What it is

Most residential blowers and many condenser fans use PSC (permanent split capacitor) motors. A PSC motor has a main (run) winding and an auxiliary (start) winding with a run capacitor in series. Multi-speed blower motors have several speed taps on the main winding. Lead colors on these motors are a maker's convention, not a code requirement. NEMA MG 1 sets standard lead markings (T-numbers) for industrial motors.

How to identify

Read the wiring label on the motor. It shows each lead's color, the speed taps, the capacitor rating and the rotation.
Rotation is stated as CW or CCW, and the label says which end it is viewed from (usually the lead end or the shaft end).
On replacement universal motors, unused speed leads must be capped and insulated.

Common lead colors (PSC blower motors)

Lead color	Common function	Notes
White	Common (neutral or L2)	Sometimes another color on 230 V motors
Black	High speed	—
Yellow	Medium or medium-high speed	Varies by maker
Blue	Medium or medium-low speed	Varies by maker
Red	Low speed	—
Brown	Capacitor	Goes to one capacitor terminal
Brown with white stripe	Capacitor	Goes to the other capacitor terminal
Green or green/yellow	Ground	To the frame or equipment ground

NEMA lead markings and rotation

Motor type	Lead markings	How rotation is reversed
Single-phase, dual-voltage	T1, T2, T3, T4 main; T5, T8 auxiliary	Interchange T5 and T8
Three-phase	T1 to T9 or T1 to T12	Interchange any two line leads
PSC with reversing leads	Per motor label	Follow the label's reversal diagram
PSC without reversing leads	—	Not reversible in the field

Key points

Swapping the two capacitor wires does not reverse a PSC motor. The capacitor has no polarity. Reversal needs the auxiliary winding's connection reversed relative to the main winding, as shown on the label.
Match the replacement capacitor µF and voltage to the motor label, not the old capacitor.
Speed taps change airflow. Set the speed from the equipment's airflow table.
ECM and other electronically commutated motors do not follow this chart.

Common mistakes

Wiring by color alone without reading the label.
Leaving unused speed leads uncapped.
Running a fan backward after replacement. Check rotation before closing up.

Governing standards: NEMA MG 1 (motor lead markings and rotation); the motor and equipment manufacturer's wiring diagrams; NEC (NFPA 70) for supply wiring.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.

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