Part Winding Start Bitzer Compressor Wiring Diagram

The Bitzer compressor, a staple in industrial refrigeration and air conditioning systems, often employs a part winding start method to reduce inrush current during startup. Understanding the part winding start Bitzer compressor wiring diagram is crucial for effective installation, maintenance, and troubleshooting. This article provides a comprehensive overview of the wiring configuration, its benefits, practical applications, and essential troubleshooting tips.

Benefits of Part Winding Start

The part winding start (PWS) method offers significant advantages compared to direct-on-line (DOL) starting, primarily related to reduced electrical stress:. For more related activities, check out our Ductlessaire Wiring Diagram.

• Reduced Inrush Current: PWS significantly lowers the initial current surge during motor startup, typically to 50-65% of the DOL current.
• Lower Mechanical Stress: Reduced torque spikes decrease mechanical stress on the compressor’s components and connected equipment.
• Cost-Effective: PWS starters are often less expensive than other reduced-voltage starting methods like autotransformer or soft starters.
• Extended Motor Life: Minimizing electrical and mechanical stresses contribute to prolonged motor lifespan.

Understanding the Wiring Diagram

A part winding start Bitzer compressor wiring diagram illustrates how the motor’s windings are divided into two or more parallel circuits. Only one circuit is energized initially. After a short delay, the remaining circuit(s) are energized, bringing the motor to full speed. Key elements of the diagram include:

• Main Motor Windings: The motor stator windings are split into two identical sets (e.g., W1-U1 and V1-U2).
• Contactors: Two contactors, typically labeled “1S1” and “1S2,” are used to energize each winding set sequentially.
• Timer: A timer relay controls the delay between energizing the first and second contactors. This delay is critical for proper motor acceleration.
• Overload Protection: Overload relays are essential for protecting the motor against overcurrent conditions.
• Control Circuit: The control circuit includes start/stop buttons, safety interlocks, and the timer relay.

It’s crucial to consult the specific Bitzer compressor model’s wiring diagram for accurate connections. Generic diagrams can be misleading, potentially causing motor damage.

Practical Application and How It Works

The part winding start method is commonly employed in Bitzer compressors used in:

• Industrial refrigeration systems
• Large air conditioning units
• Process cooling applications
• Chillers

How it works: When the start button is pressed, contactor 1S1 closes, energizing the first set of windings. This provides a reduced starting torque. After the set delay (typically a few seconds) programmed into the timer, contactor 1S2 closes, energizing the second set of windings. The motor then accelerates to its rated speed. The precise timing sequence is vital to ensure smooth acceleration and prevent excessive current draw.

1. Troubleshooting Common Issues

Diagnosing issues related to a part winding start Bitzer compressor wiring diagram requires careful examination of the system. Common problems include:

• Motor Fails to Start: Check the control circuit, contactor coils, overload relays, and wiring connections.
• Excessive Starting Current: Verify the timer relay is functioning correctly and the delay time is properly set. Inspect the motor windings for shorts or grounds.
• Contactor Failure: Check the contactor coils, contacts, and wiring connections.
• Overload Tripping: Ensure the overload relays are properly sized and calibrated. Investigate potential motor overloading or winding faults.

2. Tips for Best Practice

• Use Original Wiring Diagrams: Always refer to the specific Bitzer compressor model’s wiring diagram for accurate connections.
• Proper Wire Sizing: Use appropriately sized conductors based on the motor’s full-load amperage and applicable electrical codes.
• Regular Inspection: Regularly inspect wiring connections, contactors, and overload relays for signs of wear or damage.
• Professional Installation: Employ qualified technicians experienced with Bitzer compressors and part winding start systems.
• Voltage Monitoring: Ensure the supply voltage is within the acceptable range for the compressor motor.

FAQs

• Q: Can a part winding start motor be converted to DOL start?

  A: It is generally not recommended. Part winding start motors have different winding configurations than DOL motors. Conversion may damage the motor.

• Q: What is the typical delay time for the timer relay?

  A: The typical delay is between 2 to 5 seconds, but it depends on the motor’s size and load characteristics. Refer to the manufacturer’s specifications for the correct setting.

• Q: How do I test the timer relay?

  A: Use a multimeter to check the continuity of the timer relay’s contacts and the coil resistance. Observe the timer’s operation when energized to ensure proper timing sequence.

• Q: What happens if the timer relay fails?

  A: If the timer relay fails, the second set of windings may not energize, causing reduced torque or the motor to trip on overload. Alternatively, both sets of windings may energize simultaneously, causing a high inrush current.

Conclusion

Understanding the part winding start Bitzer compressor wiring diagram is paramount for ensuring the efficient and reliable operation of refrigeration and air conditioning systems. Proper installation, maintenance, and troubleshooting are essential for minimizing downtime, extending compressor lifespan, and preventing costly repairs. Always refer to the specific Bitzer compressor model’s documentation and employ qualified technicians for any work related to the electrical system.