PWM 8000W High-Power SCR Electronic Voltage Regulator for Motor/Fan/Drill Speed Control (0-220V Adjustable, WTH138 Model with Switch)

SKU: FA2020-7-1
Model

WTH138 (High-Power Series)
Input Voltage

AC 220V
Output Voltage

AC 0V – 220V (Adjustable)
Maximum Power

8000W (Instantaneous Resistive Load)
Continuous Working Power

3500W – 4000W (Recommended for long-term stability)
Voltage Regulation Range

0% – 100%
SCR Specification

High-current 80A / 1200V Bidirectional Thyristor
Efficiency

>90%
Dimensions

Approx. 150mm x 60mm x 47mm (Including knob and heatsink)
This PWM 8000W High-Power SCR Electronic Voltage Regulator (WTH138 Model) is a professional-grade power management solution engineered for high-wattage AC applications. Featuring a high-performance bidirectional Silicon Controlled Rectifier (SCR), this unit provides seamless, stepless control over the voltage output, making it an essential tool for managing the performance of heavy-duty industrial and domestic equipment.
The WTH138 model is specifically designed for versatility, featuring an integrated physical power switch on the potentiometer. This allows users to completely cut the circuit without unplugging the device, ensuring both precision and safety. Whether you are regulating the speed of a high-torque drill, the temperature of an industrial furnace, or the airflow of a large exhaust fan, this regulator provides the stability and power handling required for 24/7 operation.
Key Features
  • Massive 8000W Peak Capacity: Specifically built to handle high-surge resistive loads like industrial heaters, electric kilns, and large-scale lighting arrays.
  • Integrated WTH138 Switch: The precision potentiometer includes a tactile “click” ON/OFF switch for instant circuit isolation.
  • Advanced Dual-Inductance Design: Features dual-high-current inductors and a professional RC snubber circuit to filter electrical noise and protect the SCR from inductive voltage spikes.
  • Stepless PWM-Style Regulation: Provides a smooth, linear output curve from 0V to 220V, allowing for granular control at low speeds or low heat levels.
  • Industrial-Grade Heat Dissipation: Equipped with an oversized, thickened aluminum heatsink and a reinforced PCB to maintain thermal stability under heavy current loads.
  • Flame-Retardant Construction: Built with high-temperature resistant materials and heavy-duty screw terminals for secure, low-resistance high-gauge wiring.
Usage Guidelines
  1. Wiring: Connect the AC input (220V) to the IN terminals and your equipment to the OUT terminals. Warning: You must connect a load (e.g., a motor or heater) before the voltage can be measured or adjusted.
  2. Startup: Turn the knob counter-clockwise until it “clicks” to the OFF position. Plug in the power, then click ON and slowly rotate clockwise.
  3. Adjustment: Rotate the knob clockwise to increase the power. Monitor the equipment’s response (RPM, heat intensity, or brightness) to find the ideal setting.
  4. Load Management:
    • Resistive Loads: (Heaters, Ovens, Incandescent Lamps) Safe up to 8000W peak.
    • Inductive Loads: (Brushed Power Tools, Fans, Sump Pumps) Should not exceed 2500W–3000W to account for high starting inrush current.
  5. Placement: Ensure the heatsink is not obstructed. For business use in enclosed panels, we recommend adding a 12V cooling fan to ensure maximum longevity of the SCR.
Q: Can I use this for the speed control of a large air conditioner or refrigerator?

No. This regulator is designed for Brushed (Universal) Motors. Most refrigerators and large AC units use induction motors with start capacitors, which are not compatible with phase-cut voltage regulators.

Q: Why is the continuous power rating much lower than the 8000W peak?

8000W is the “surge” limit for resistive loads. For business and industrial users running equipment for hours at a time, we recommend a 3500W-4000W limit to prevent thermal fatigue and ensure the internal components last for years.

Q: Will this work to dim LED lights?

This unit is a “Leading Edge” Triac dimmer. It works perfectly with incandescent and halogen bulbs. It is generally not compatible with LED bulbs unless the bulbs are specifically labeled as “Triac Dimmable” and the total wattage exceeds the minimum holding current of the 80A SCR.

Q: How does the "0-220V" adjustment work?

Unlike lower-wattage models that start at 50V, the high-performance circuit in the 8000W model allows for a near-zero start, which is excellent for very slow-moving fans or low-intensity heating.

Q: Is this suitable for commercial catering or industrial furnaces?

Absolutely. Business purchasers frequently use this for commercial griddles, industrial plastic extrusion heaters, and high-power workshop tools. Its high-current 80A thyristor provides a significant safety margin for commercial duty cycles.

Q: Does it produce electromagnetic interference (EMI)?

Like all high-power SCR controllers, it produces some electrical noise. While it includes an RC absorption circuit, it should be kept away from sensitive audio/video or medical diagnostic equipment.

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