Blogs from August, 2023

  • Clear All

Benefits: Soft Start Compared to HSK

Mark Sr Tech
  1. A hard start kit and a soft start are both devices used to assist in the startup of electrical motors, such as those found in air conditioning (AC) units, refrigerators, and other appliances. However, they serve different purposes and operate in distinct ways. Here's a comparison of the two:

    Hard Start Kit:

    A hard start kit is also known as a start capacitor kit or compressor saver. Its main purpose is to assist the AC compressor during startup, particularly when there are issues related to high starting torque requirements. The compressor is the most power-hungry component of an AC unit, and starting it up can require a significant surge of current.

    How It Works: A hard start kit includes an additional start capacitor and a potential relay. When the AC unit starts, the extra capacitor provides an extra boost of energy to the compressor, helping it overcome the high starting load. The potential relay helps switch the extra capacitor in and out of the circuit as needed during startup.


  2. Helps prevent damage to the compressor by reducing strain during startup.
  3. Can extend the lifespan of the compressor.
  4. Minimizes the risk of lights dimming or circuit breakers tripping when the AC starts.
  5. Soft Start:

    A soft start, also known as a soft starter, is designed to reduce the inrush current during motor startup for a variety of electrical equipment, not just compressors. It provides a smoother and more gradual increase in voltage and current to the motor, which reduces stress on both the motor and the electrical system.

    How It Works: A soft start uses electronics to control the voltage applied to the motor, gradually ramping it up over a period of time. This avoids the sudden surge of current that occurs during traditional motor startup.


  6. Reduces stress on the motor and associated components.
  7. Extends the lifespan of the motor.
  8. Lowers energy consumption by minimizing inrush current.
  9. Improves stability of the power supply, particularly in areas with weak or unstable grids.
  10. Key Differences:

  11. Purpose: A hard start kit is specifically focused on helping AC compressors with high starting torque requirements, while a soft start is designed for a broader range of electrical motors.

  12. Operation: A hard start kit uses an additional capacitor and relay to provide a momentary boost during startup, whereas a soft start gradually ramps up voltage to reduce inrush current.

  13. Applications: Hard start kits are commonly used in AC units, while soft starts can be applied to various types of motors and equipment.

  14. Benefits: Both devices offer benefits such as extending the lifespan of motors and reducing strain, but a soft start has the additional advantage of energy savings and improved power supply stability..