WG840595 – EVAPORATOR MOTOR (1HP, 115V, 3SPD, 20MFD)

U.S. MOTORS (Nidec) direct-drive fan and blower motor, 1 HP, 1075 RPM, 3 speed, 115 V, 6 pole, 12.1 A. Permanent split capacitor design with an open air-over enclosure and a 1/2 in. shaft, used in evaporator and air handler blower duty. The published run capacitor is 20 MFD, matching our stock record.

Specifications published by the manufacturer. Source: manufacturer documentation.

Specs

• BrandU.S. MOTORS (Nidec)
• Horsepower1 HP
• RPM / speeds1075 RPM, 3 speed
• Voltage115 V, 1 Ph
• Amps12.1 A
• Poles6
• Run capacitor20 MFD
• Motor typePSC, direct drive fan/blower
• EnclosureOAO (open air over)
• Shaft0.500 in. dia

Cross-reference numbers

This part replaces the following OEM and aftermarket numbers:

• 8906
• 69M79
• S1-02440900000
• S1-024-40900-000
• 024-32056-000
• 02440900000
• S1-024-36289-000
• GY8S100C20UH11C
• TGLS100C20MP11A

Not sure if your number matches? Call (214) 340-9421 or bring the old part in — bench-testing is free.

Is a 1075 RPM motor different from an 1100 RPM motor?

No. Both are 6-pole motors with a nominal speed of 1200 RPM, and the published number is just each manufacturer's rating convention. Anything in the 1050 to 1140 range is the same speed class. Pole count is what actually matters: 2-pole is nominal 3600 (published 3200 to 3450), 4-pole 1800 (1625 to 1750), 6-pole 1200 (1050 to 1140), 8-pole 900 (800 to 850). Swap a 6-pole for a 4-pole and you have a different motor entirely. Do not chase 25 RPM.

Can I put a PSC motor in place of an X13 or a variable-speed ECM?

Not as a straight drop-in. An X13 is a constant-torque motor that takes 24 volt signals on tap terminals instead of speed leads. A variable-speed ECM holds a target CFM by ramping against the static pressure it sees. A PSC has no idea what static pressure is, so you pick one speed tap and live with it. On a duct system pulling 0.8 inches water column of total external static, a PSC will not give you the airflow back. Genteq Evergreen style ECM replacements exist, but they still have to match frame, shaft and rotation.

What has to match besides horsepower?

Frame size, shaft diameter and length, rotation, mounting style, voltage and the run capacitor rating. A 48 frame motor is 5-1/2 inches across the body, a 42 frame is 5 inches. Keep amp draw within about 5 percent of the old nameplate, and never step horsepower DOWN.

Do I need a new capacitor with a PSC blower motor?

Yes. The new motor's nameplate tells you the microfarad it wants, and a weak capacitor is what killed a fair number of the motors that come across our counter.