Manual Variable Resistance Control

Flexible Control for Advanced Applications

Applications that require excellent efficiency in high-voltage, high-power conditions require sophisticated control options. Manual variable resistor control (RPWM) technology plays a vital role in maximizing performance and reliability in applications that require manual speed control at variable levels. 

RPWM technology utilizes an external variable resistor to manually control the fan speed in linear relation to the resistor value. This type of control is essential for applications such as electric welding controls, DC motor drives, controls for generators, and more.

Advanced Technology to Control Speeds

A number of control options are also included when using manual variable resistance control technology, including constant speed (CS), inrush current protection (IR), and current limit (CL).

  • Constant Speed (CS) — This control is set externally to keep devices such as motors running at a constant speed. CS is attained by monitoring the applied voltage and the current to the motor.. The values of these factors are calculated and the speed is adjusted to remain constant to ensure the desired maximum RPM and noise level. If the applied voltage is increased, the applied current will decrease, maintaining the power of the motor constant. Using constant power technique, the safe operation of the motor is ensured when the applied voltage exceeds the rated value.  
  • Inrush Current Protection (IR) — To avoid gradual damage to components and tripping circuit breakers or fuses, manual variable resistor controls implement IR. The current is applied gradually to the motor when the motor is powered up.
  • Current Limit (CL) — Similar to IR, this limit is important for protecting the circuit of the device from the effects of short-circuiting or other overload problems. This is often accomplished by using a fuse; however, in the case of electronic power circuits, active current limiting is employed instead due to their faster response. Circuitry is arranged to create a protective mechanism that prevents overloading damage during operation.

RPWM technology is available in three different modes: A, B, and C. Selection of the appropriate mode for a specific application depends on resistor value and percentage.

Essential Component for Fans and Motorsdc-blower.jpg

At Pelonis, we design and fabricate all types of high-tech solutions, including those that require RPWM controls. Some of these applications include a high-efficiency DC fan that was built directly into a medical application. This customized fan met all of our client’s specifications for reliability and high performance.

We also have used RPWM controls in specially designed DC blowers. For these products, variable resistance control helps ensure longevity and long-term reliability. 

Contact Us for More Information

We not only work with advanced technology, but strive every day to provide our customers with the best quality and value for custom fan and related technologies. To learn more about how RPWM controls provide enhanced quality, efficiency, and lifespans for your high-tech applications, download our eBook, Fan Speed Controls.

Download the Fan Speed Controls eBook