Adding a VFD to a non-VFD Motor

VFDs Cannot Be Added to Single-Phase Motors
If you're considering purchasing a grinder without a VFD and planning to upgrade later, it's important to know: You cannot add a VFD to a single-phase motor. If you buy one of our grinders bundled with a motor but no VFD, it will come with a single-phase 110V motor that is not VFD-compatible.

Why Can’t a VFD Be Added Later?
Here’s a breakdown of the technical reasons:

Single-phase motors are built differently than three-phase motors. They rely on a starting circuit with a capacitor and a mechanical centrifugal switch that disengages after startup. This type of design is not compatible with how VFDs control speed.

Winding differences between single-phase and three-phase motors often prevent any retrofit. In some cases, rewinding the motor is required, which is more costly than simply using the correct motor upfront.

Speed control issues: Even with workarounds, single-phase motors struggle to maintain low-speed torque and control when paired with a VFD.

No reliable VFDs for single-phase motors: After extensive testing, we have yet to find a dependable, long-term solution for pairing single-phase motors with VFDs.

Summary
Although it's technically possible to run a VFD on a single-phase motor, the drawbacks—reliability issues, cost, and poor speed control—make it a bad idea. If you're looking for variable speed control, it's best to choose a 3-phase motor with a VFD from the start.

Diktator Motor Packages
We offer three main options:

1.5 HP Motor (Single Speed, No VFD)

1.0 HP Motor with VFD (110v or 220v)

2.0 HP Motor with VFD (110v or 220v)

All VFD-compatible motors are 3-phase, and the VFD converts your household 110V or 220V power into 3-phase output, giving you full control over speed and performance.

Still unsure which motor is right for your setup? Contact us at support@diktatorgrinder.com—we’re happy to help.