Product Overview
The LiftMaster K29-10338 is a replacement motor capacitor rated 70 MFD, 230VAC, 50/60Hz. In compatible commercial door operators, the capacitor is part of the motor circuit and helps the motor start and run with the correct phase shift. A correctly matched capacitor is important for reliable motor performance, especially on commercial operators that lift heavier sectional, rolling, or hoist-style doors.
This capacitor is used across several LiftMaster light-duty and medium-duty commercial operator families. It is especially important to match the capacitor value and voltage rating exactly. Installing a capacitor with the wrong MFD rating can cause poor starting, motor overheating, nuisance tripping, or premature motor failure. The physical size and terminal style should also be checked because older replacement parts and motor kits may have slight packaging differences.
A failed capacitor is often suspected when a compatible operator hums, starts slowly, needs help to move, or trips protection after attempting to run. However, those symptoms can also come from a seized door, failed brake release, worn motor bearings, incorrect incoming voltage, damaged wiring, or a control station problem. The capacitor should be tested and replaced only within the correct service procedure.
Compatible With
Confirmed and commonly referenced compatible operator families include the following LiftMaster commercial door operators when the parts diagram specifies a 70 MFD 230VAC capacitor.
- MT commercial trolley operators
- BMT commercial trolley operators
- MJ medium-duty jackshaft operators
- MH medium-duty hoist operators
- HMJ commercial hoist/jackshaft operators
- MHS medium-duty slow-speed hoist operators
- LGO light-duty commercial operators
- MGJ medium-duty gear-reduced jackshaft operators
- Other LiftMaster light-duty and medium-duty commercial door operators only when the parts diagram lists K29-10338 or one of the related numbers
Do not substitute by size alone. Match the 70 MFD rating, 230VAC rating, frequency, terminal style, and the operator wiring diagram.
Also Known As / Related Part Numbers
- K29-10338
- 29-10338
- 30B432
- 29-3530
- G293530
- 70 MFD capacitor
- 70 uF capacitor
- 230VAC motor capacitor
Features & Specifications
| Feature / Specification | Details |
|---|
| Manufacturer | LiftMaster |
| Product Type | Motor capacitor |
| Part Number | K29-10338 |
| Capacitance | 70 MFD |
| Voltage | 230VAC |
| Frequency | 50/60Hz |
| Application | Motor circuit on select commercial door operators |
| Compatible Operator Type | Light-duty and medium-duty commercial door operators |
| Related Numbers | 29-10338, 30B432, 29-3530, G293530 |
Technician Note
A capacitor can test weak under load even if it looks normal from the outside. Bulging, leaking, burnt terminals, or repeated motor hum should be treated as a sign to inspect the entire motor circuit, not just the capacitor.
Before Ordering
- Verify the operator model and motor voltage.
- Match the original capacitor to 70 MFD and 230VAC.
- Check the related part number on the parts diagram.
- Inspect motor leads, brake operation, door balance, and incoming voltage.
- Have stored energy in the capacitor handled safely by a qualified technician.
Professional Advisory
This part is connected to an electrical motor circuit. Do not work on the capacitor or operator wiring with power applied. Commercial door electrical diagnosis should be performed by a qualified technician familiar with high-voltage operator circuits.
Product Questions & Answers
What rating is the K29-10338 capacitor?
It is a 70 MFD motor capacitor rated 230VAC and 50/60Hz.
Which LiftMaster operators commonly use this capacitor?
It is commonly listed for MT, BMT, MJ, MH, HMJ, MHS, LGO, and MGJ commercial door operator families when the parts diagram calls for it.
Can I replace it with a different MFD capacitor?
No. The MFD and voltage rating should match the operator requirement. A wrong value can damage the motor or cause poor operation.
What symptoms can a bad capacitor cause?
A weak capacitor can cause humming, slow starting, failure to start, overheating, or intermittent motor operation on compatible single-phase systems.
Is this a safe DIY repair?
Capacitors and commercial door motors can involve stored charge and line voltage. A qualified commercial door technician is recommended.
