LiftMaster 3PHCONV Transformer Kit — 208/240/480/575V AC Input to 120V AC

The LiftMaster 3PHCONV transformer kit adapts a supported gate operator to an approved higher-voltage supply arrangement by providing 120V AC output from the selected 208, 240, 480 or 575V AC input. Despite the three-phase wording often used in its sales name, the manufacturer specifies a single-phase transformer input rating. It does not convert the gate motor into a three-phase motor. Selection also depends on the exact operator, accessory-outlet load and available space for batteries or a heater.

Compatibility — Models, Versions and Exclusions

Check Electrical Selection and Cabinet Space Together

A qualified electrician must identify the supply and select the correct transformer connection using the kit instructions and equipment rating. The available building service is not permission to connect the operator directly to that voltage. The installation includes replacement rating labels because both the operator input information and accessory-outlet limits change.

Mechanical fit also matters. Battery placement and heater clearance vary by operator. The CSW24U/UL arrangement requires the batteries on a separate upper tray identified as K75-37099, while the HD slide and swing arrangements have a specific 33Ah battery exclusion. Review the actual cabinet layout before ordering; a transformer that is electrically suitable can still conflict with the installed accessories.

Specifications and Product Identification

Before Ordering

• Record the exact operator model and existing battery and heater configuration.
• Have an electrician verify supply voltage, phase arrangement and the required protection.
• Check the model-specific mounting drawing and any separately required battery tray.
• Account for the new accessory-outlet rating and apply the required equipment labels during installation.

Package Contents and Separate Requirements

The manufacturer inventory includes the transformer and bracket, routing sleeve, bushing, cable ties, wire connectors, specified mounting hardware and replacement rating labels. Confirm the current revision and required model-specific parts. A separate battery tray, site circuit work and operator are not established as included. The complete mounting and wiring procedure must follow the supplied instructions.

Safety Warnings — Read Before Installation or Service

• WARNING: This kit connects to hazardous line voltage. Installation and electrical connections require a qualified professional.
• Disconnect all electrical and battery power before installation. Verify isolation before touching conductors.
• Use the correct input connection and protect unused leads as instructed. Maintain the required separation between line-voltage and low-voltage wiring.
• Observe the revised accessory-outlet rating and installation clearances, then test the operator and all required protection devices before normal service.

Related Products and Important Differences

• LMRRUL monitored photo eye — a separate protection accessory for approved operator configurations; it is not connected directly to the transformer primary.
• LMWEKITU monitored wireless edge kit — a separate safety system whose power and wiring remain governed by the operator instructions.

Frequently Asked Questions

Does this turn my gate motor into a three-phase motor?

No. It provides the specified 120V AC output for supported operator arrangements; the instructions rate the transformer input as single phase.

Can it fit beside 33Ah batteries in HDSL24UL?

The referenced instructions say the HD slide and swing arrangements cannot accommodate those batteries with the transformer installed.

Can I retain the original outlet load rating?

No. Follow the model-specific revised rating and the supplied accessory-outlet label.

Does it work in every LiftMaster operator?

No. Use only the listed models and the applicable installation instructions for the supplied kit revision.

Need Help Confirming the Right Product?

Contact Garage-DoorParts.com before ordering. Send the full equipment model, readable part labels and photographs of the installed assembly. Include the dimensions, electrical configuration or accessory details relevant to your project so the listing can be checked against the actual installation.