Liftmaster K20-1050B-1L, MOTOR, 1/2HP, 115V,1PH, BM
The LiftMaster K20-1050B-1L is an older 1/2 HP, 115V, single-phase base-mount motor part number used in LiftMaster gate operator service. Some current listings indicate that it has been replaced by the K20-1050B-1RL / Q018 motor family, which makes part-number confirmation especially important before ordering.
Motor supersessions can be safe when the replacement is a factory-approved equivalent, but they still need to match the operator application. Mounting base, shaft length, keyway, wiring leads, enclosure style, duty cycle, and voltage/phase must all be correct. This row should be handled as an older motor reference that may ship under the newer K20-1050B-1RL / Q018 number depending on supplier stock.
Compatible With
- Select LiftMaster 1-phase gate operators originally calling for K20-1050B-1L
- Various 115V 1-phase LiftMaster gate operator applications where the matching base-mount motor is shown by parts diagram
- Applications where K20-1050B-1RL / Q018 is confirmed as the factory replacement for K20-1050B-1L
- Legacy Elite / LiftMaster operator assemblies requiring the matching 1/2 HP base-mount motor
Compatibility note: This older number is commonly referenced as replaced by K20-1050B-1RL / Q018. Confirm supersession, shaft, base, and wiring before ordering.
Features and Specifications
| Manufacturer | LiftMaster |
| Product Type | Motor replacement kit |
| Part Number | K20-1050B-1L |
| Common Replacement Reference | K20-1050B-1RL / Q018 |
| Horsepower | 1/2 HP |
| Voltage | 115V |
| Phase | 1-phase |
| Mount Style | Base mount / resilient base references |
Also Known As / Related Part Numbers
- K20-1050B-1L
- 20-1050B-1L
- K20-1050B-1RL
- 20-1050B-1RL
- Q018
- Q018A
- LM-K20-1050B-1L
- LiftMaster 1/2HP 115V motor
Technician Note
When an older motor part number has been superseded, compare the replacement motor physically before final installation. Pay close attention to shaft length, mounting holes, keyway, pulley/sprocket alignment, and wiring diagram.
Before Ordering Checklist
- Confirm whether the old motor label says K20-1050B-1L
- Verify the approved replacement is K20-1050B-1RL / Q018 for the specific operator
- Match horsepower, voltage, phase, shaft, and mount style
- Inspect the capacitor, overload, and operator drivetrain before replacing the motor
- Do not substitute a motor based on horsepower alone
Professional Advisory
This is a high-voltage motor part. Motor wiring and troubleshooting should be handled by a qualified gate technician or electrician familiar with the operator.
Product Questions and Answers
Has K20-1050B-1L been replaced by another number?
Many current references show K20-1050B-1L as replaced by K20-1050B-1RL / Q018, but the replacement should be confirmed for the specific operator.
Is K20-1050B-1L the same as K20-1050B-1RSX?
No. They are different motor references and should not be treated as interchangeable without a parts diagram.
What should I compare on the replacement motor?
Compare horsepower, voltage, phase, shaft length, keyway, mounting base, enclosure, wiring leads, and pulley or sprocket alignment.
Can a bad gate cause motor failure?
Yes. A dragging or unbalanced gate can overload the motor and cause repeated failures.
Should this be installed by a technician?
Yes. Motor replacement requires safe electrical work and final gate safety testing.
