CV switch for capacitor start induction motors

CV SINPAC® Switches for Capacitor Start Induction Motors

Features & Benefits

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  • Our solid-state switch is superior to mechanical switches
  • Extends the life and reliability of the motor, especially for high-cycling or “dirty” environments
  • Fast and easy to install and replace mechanical switches
  • Sealed, spark-free switch for challenging environments
  • Our parts work for a variety of motor manufacturers
  • Capacitor Start motors only
  • A few SINPAC® switches sizes replace dozens of mechanical switches

hero detail
Max Motor HP (Typical) 3
Switch Rating 16, 25, 40, 50 Amp
Start Circuit 115V

Questions about Modifications? Contact Customer Support

Phone: 414-272-1100
Email: [email protected]

Stearns Brakes

SINPAC Solid State Switch Installation

Frequently Asked Questions

Explain the breakdown of the switch part number?

The 12 digit part number that begins with 4-7 is broken down and explained on page 5 of the SINPAC Catalog.

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How do I select a SINPAC switch for my motor?

1. Be sure switch series matches motor type (a single phase motor is a capacitor start only, or a capacitor start/capacitor run, or if the application is for an instant reversing motor).

2. Be sure switch voltage rating matches (start) circuit voltage rating.

3. Selection can be based on actual measurement of start capacitor current or two times the motor nameplate FLA rating.

4. Switch current rating must match or exceed the motor start capacitor current requirements. Always select a SINPAC Switch with the next higher current rating for:

  • High cycling applications.
  • Long acceleration time.
  • High ambients: Greater than 55° C.

5. To assure proper motor operation, the voltage across the start winding must reach the SINPAC Switch cut out voltage reference between 70% and 85% of motors synchronous speed.

Caution: SINPAC Switches are line voltage compensated. Changes in the line voltage will not affect system operation unless an overload condition causes reduced running speed, along with reduced voltage on the start winding.

6. Higher current switches can be used in place of lower rated switches of the same series.

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What is the duty cycle SINPAC switches can operate at?

This is dependent on actual switch used, current draw, ambient temperature, and time the switch is engaged - e.g., 3S or 1/2S. CV and VR switches have been tested at 2-3 cycles per minute under normal conditions. IR switches have been tested at 1 cycle per minute under normal conditions.

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Why won't my SINPAC switch work with my motor?

Reference the Stearns SINPAC Catalog, and assure that the proper switch has been selected based on Motor Horsepower, Motor Start Circuit voltage, full load motor amps, and proper cut-out voltage.

View SINPAC Switch Catalog

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