Basic Operation
Capacitor start/capacitor run motors and capacitor start motors provide continuous voltage sensing information which can be used to extract speed data from the voltage across the motor start (auxiliary) winding. By comparing this start (auxiliary) winding RPM-sensitive voltage to the main AC input voltage (which serves as a reference voltage), the switch determines when the start circuit should be de-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 decreased to a preselected cut in RPM level.
Capacitor start/capacitor run motors exhibit current transients and higher voltages across the start switch. This electrical stress is due to the voltage differential which may exist between the start and run capacitors at the instant of switch closure. This stress phenomenon occurs with both mechanical and electronic type start switches. SINPAC Switches have voltage detection circuitry to minimize the effects of these conditions.
1. Universal Design: 50/60 Hz operation. Will work on 2, 4 or 6 pole motors of any manufacturer. Reduced inventory.
2. Line Voltage Compensation: Operating voltage 190 to 260 Vac.
3. Electrically Protected: Designed to filter out electrical noise, so there is no concern of random switch malfunction.
4. Zero Crossing Logic: Current spiking due to run capacitor no longer a problem.
5. Speed Sensitive
6. Soldered Heat Sink: High cycling.
7. Environmentally Protected: Immune to moisture, dust, dirt, shock and vibration.
8. Transient Protection: Transient protection tested per IEEE C62.41 - 1991 Category A3.
9. Start Capacitor Discharge Resistor: Increase start capacitor life.
General Information
| Typical Max Motor Horsepower (HP) |
5 HP |
| Typical Full Load Motor Nameplate Current Rating (Amps) |
25 Amps @ 230 Volts |
| Switch Rating & Permissible Maximum Start Circuit Current (Amps) |
50 Amps |
| Start Circuit Voltage |
230 |
| Cut Out Voltage (Typical) |
260 Volts |
| Cut In Voltage Typical |
70 Volts |
| Package Style |
15 |
| Catalog Number |
2VR-50-260 |
| Part Number |
Stearns 4-7-72050-15-UC1
Stearns Kit 4-7-72050-15-UCK
SAP Part# 10550784 |
| 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 |
230 Vac SINPAC Switch: 190-255 Vac. |
| UL Recognition (E71115) to US and Canadian Standards |
| UPC |
662327713713 |
Additional Features
Completely Solid-State with No Moving Parts: SINPAC Switches have no physical constraints to affect their operation. No wearing parts mean high cycling, no arcing contact.
Silent Operation: No switch noise
Ambient 40° to 65°C.
Selection
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 auxiliary (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. SINPAC Switches are line voltage compensated. Changes in the line voltage will not effect 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 greater than the switch cut-out voltage to assure cut-out of the start capacitor. Refer to charts ABOVE.