Permanent Split Capacitor (PSC) Motor Lead Identification
In case you couldn't tell from the title, this article addresses PSC motor lead identification. A PSC motor is a single phase motor that uses a run capacitor; pretty straight forward until you need to replace one and the new motor has different lead colors, or a different number of leads.
PSC motors come in a variety of flavors: single speed, multi speed, single capacitor wire, and double capacitor wire. They also come in different frame sizes, shaft sizes, horsepower ratings, RPM ratings, case styles, bearing styles, double or single shaft, clockwise / counter clockwise /reversible rotations, and different voltages....(did I forget anything?) But this article is about identifying the motor leads.
Let's start with capacitor leads; every PSC motor has a run capacitor. Most motors have two leads for the capacitor; one brown, the other brown with a white stripe. Some motors only have one brown capacitor wire; this is where the confusion starts. The brown wire with the white stripe is connected internally to the motors common "line" lead. If the new motor does not have a white striped brown wire, simply connect the one terminal of the capacitor to the solid brown wire, and connect the other capacitor terminal to the motor's common lead and to line.
So far so good; we know that-
• The white wire is common and is connected to line.
• A brown wire with a white trace is connected to the white common wire internally in the motor and it connects to one of the run capacitor terminals.
• The solid brown wire connects to the other terminal on the run capacitor.
Now, let's look at the other motor leads. Black is normally high speed. Blue is normally medium speed. Red is normally low speed. Some motors may also have a yellow wire that is normally medium-low. Green, or green with a yellow stripe is always ground.
Can some motors have different color designations? Yes! So always double check the motor manufacturer's data before wiring; guessing is never an option.