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472102511U03 Stearns® SINPAC® Electronic Switch

Product ID: CV25-165

MFG: Stearns/Rexnord Corporation
MFG Part Number: 4-7-21025-11-U03

Selected accessories will also be added to cart
$55.70 / Each
115V, 25A, 165V Cutout, 50/60Hz, 002785.02, 472102511U02
Available Stock: 1

CV Series for 115 Vac or 115/230 Vac Dual Voltage Capacitor Start Motors

Basic Operation

Capacitor start motors require a method to extract speed data from the voltage across the motor start winding. By comparing the start winding RPM-sensitive voltage with the main AC input voltage (which serves as a reference voltage), the switch determines when the start circuit should be energized. The electronic switch interrupts the start circuit current after the motor has accelerated to the cut out speed, and reconnects the start circuit whenever the motor speed has fallen to cut in speed (usually about 50% of synchronous motor speed).

1. Electrically Protected: Designed to filter out electrical noise, so there is no concern of random switch malfunction.

2. Reduced Installation Time: Easily accessible 1/4 inch terminals and mounting, reduce the amount of time required to install SINPAC Switches or to change out mechanical switches.

3. Restart Capability: When motor speed drops below 50% of synchronous speed, the start circuit is reconnected to reinitiate starting torque.

4. Soldered Heat Sink: High cycling.

5. Transient Protection: Transient protection tested per IEEE C62.41 – 1991 Category A3.

6. Universal Design 50/60 Hz operation. Will work on 2, 4 or 6 pole motors of any manufacturer. Reduced inventory.

7. Line Voltage Compensation: No modifications or changes are required for line voltage variations. SINPAC Switches will operate in areas susceptible to brownouts or low voltage due to long wiring runs. It also means there will be less stress on the starting capacitor due to over voltage.

General Information

Typical Max Motor Horsepower (HP) 1 HP
Typical Full Load Motor Nameplate Current Rating (Amps) 12 Amps @ 115 Volts
12/6 Amps @ 115/230 Volts
Switch Rating & Permissible Maximum Start Circuit Current (Amps) 25 Amps
Start Circuit Voltage 115
Cut Out Voltage (Typical) 165
Cut In Voltage Typical 37
Package Style 11
Catalog Number CV-25-165
Part Number Stearns 4-7-21025-11-U03
Leeson 002785.02
Replaces Old Stearns 4-7-21025-11-U02

Additional Features

UL Recognition (E71115) to US and Canadian Standards
Operating Temperature -40°C to 65°C (-40°F to 149°F)
For Operation between 65°C and 85°C (149°F and 185°F), Consult Factory.
Operating Voltage 115 Vac SINPAC Switch: 90-130 Vac
For Dual Voltage motor equipped with center-tapped main winding: 90-130 Vac or 180-265 Vac.


Motor HP ratings are typical. For an accurate selection procedure, measure start capacitor current during a normal start or at locked rotor and select a SINPAC Switch with higher maximum current rating than that measured.

1. Be sure switch series matches motor type.

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:
a) High cycling applications.
b) Long acceleration time.
c) 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 reference voltage between 70% to 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 across the start winding.

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

Line Voltage Compensation Charts

Induced voltage across the start winding is directly proportional to motor speed and line voltage. All SINPAC Switches use this voltage to switch the start capacitor out of the circuit. Your motor with a SINPAC Switch must generate a voltage that is 20% greater than the switch cut out voltage to assure cut out of the start capacitor. Refer to charts above.