Fan Regulator Connection & Harmonic Testing

Introduction

Fan regulators are commonly used to control the speed of ceiling fans. This test examines the connection methods and harmonic characteristics of a typical fan regulator when used with a ceiling fan.

Test Setup

Test setup showing fan regulator connection to THDPM-1

Wiring diagram for fan regulator connection

Connection Method

The fan regulator is connected in series with the fan motor. The regulator controls the voltage supplied to the motor by varying the phase angle of the AC waveform.

1. Connect the input terminals of the regulator to the AC power source
2. Connect the output terminals of the regulator to the fan motor
3. Ensure proper grounding of the regulator and fan
4. Connect the THDPM-1 in parallel to measure voltage and current

Test Parameters

Harmonic Analysis Results

Harmonic Spectrum

The harmonic spectrum shows increasing THD as the speed setting is reduced. The triac-based phase control introduces significant current harmonics, particularly at lower speeds.

Observations

• Voltage THD increases with lower speed settings due to phase control
• Current THD is significantly higher than voltage THD at all settings
• Power factor decreases as speed is reduced
• The 3rd, 5th, and 7th harmonics are most prominent

Recommendations

• For sensitive electronic equipment, consider using electronic fan controllers instead of triac-based regulators
• Install harmonic filters if high THD levels are problematic
• Regular maintenance of fan regulators can help maintain performance