Static Phase Converter Guide

Static Phase Converter Guide

Understanding static phase converters can help you determine whether or not you need a rotary phase converter instead for your application.

What is a static phase converter?

static phase converter is a startup device for three phase motors running on single phase power. They generate three phase power only long enough for the motor to start up, not continuously like a rotary phase converter would.

Once the three phase motor has started up, the static phase converter circuitry disconnects itself, and the motor continuse to run on single phase power. Two of the three windings receive power during running, so horsepower output is reduced to between 2/3 to 1/2 of the rated motor horsepower. For example, a 20 HP motor will start with the power of a 20 HP motor but run as a 10 HP motor.


Static phase converters are more cost effective than rotary phase converters on equipment that statics work on. Rotary phase converters are usually used to operate multiple machines, while static phase converters are used to operate a single machine.

What motors work on static phase converters?

The two most common types of three phase motors are Wye or Delta wound. Delta wound motors are more common as the horsepower rating increases. Many imported motors are Delta connected and occasionally only work on a TEMCo Rotary Phase Converter.

The continous full three phase power of TEMCo's rotary phase converters can run either Wye or Delta motors or any other application that requires three phase power efficiently and reliably. The following guidelines will help you determine whether a static or rotary phase converter is right for you.

1) Do I need to only operate a three phase motor on single phase? If yes, view question 2. If your equipment has electronic controls, use a rotary phase converter.

2) Can my machine operate with full horsepower on startup and reduced horsepower when running? If yes, then a static phase converter is suitable for your application.

Equipment that often works on static phase converters Some machines that will work when modified after the motor pulley is reduced by half in size Machines that will NOT work on a static

Drill press
Milling Machine
Table Saw

These are all devices where the operator controls the load on the motor.

Air compressor
Belt-driven fan

These machines work because the motor load can be reduced by changing the pulley size.

Water pump
Hydraulic car lift
Dust collector

These machines use the full rated horsepower of the motors that are on them and should only be supplied three phase power from a TEMCo Rotary Phase Converter or the utility.

Product Selection

TEMCo XS Static Wave Static Phase Converter

Product Line: STATIC WAVE
Voltage: 208 - 240
Frequency: 50/60 Hz
Acceptable Load Types:Light to moderately loaded motor loads only.
Country of Manufacture: USA

Application Notes

For light to moderate starting or running loads only. See acceptable loads in the chart below.

Intended for wye wound motors. Some delta wound motors may operate but will produce 50% of their nameplate HP.

Motors will produce 2/3 of rated HP.

Special Loads:
- Lathes 3 HP and larger must have a clutch and be started or reversed only while disengaged.

- May be used for air compressors but should have the motor pully size reduced by 1/3 in diameter. Alternately, a motor that is 50% larger may be fitted.

Part Number Min/Max HP (Load) Voltage Hz Max 1 Phase Amps
XS0 1/3 to 3/4 208 to 240 50/60 2.8
XS1 3/4 to 1 1/2 5.2
XS3 1 to 3 10
XS5 3 to 5 17
XS8 4 to 8 22
XS12 8 to 1 33.6

Acceptable Load Types Not Recommended
Easy Medium Hard

Bench grinder
Chop saw (1 HP & under)
Drill press (2 HP & under)
Meat slicer/cutter
Table saw (2 HP & under)
Lathe (2 HP & below)

Band saw (belt drive)
Dough Mixer
Meat grinder
Panel saw
Radial arm saw
Tumbler (below 5 HP)
Table saw (above 2 HP)
Conveyer belt (horizontal)
Industrial washing machine
Milling machine
Pump (above ground)
Sewing machines
Masonry saw
Lathe (2 HP and above)

Air compressor
Band saw (direct drive)
Car lift
Dust collection blower
Granite saw
Iron worker
Lathe (above 2 HP or w/o clutch)
Thickness planer
Vacuum pump