how to replace bench grinder capacitor

How To Replace Bench Grinder Capacitor | 5 Simple Steps

Bench grinder capacitor failure can be a frustrating experience, as it can lead to a variety of problems with your machine, from decreased performance to complete machine failure. We’ll provide you with the steps necessary how to replace bench grinder capacitor and help you avoid common problems that can occur. We’ll also provide tips on how to test your machine’s capacitors and identify any issues before they cause major problems.

Steps to Replace the Capacitor

Step No. 1: Turn off the power to the machine by disconnecting the power cord from the wall outlet.

Step No. 2: Disconnect capacitor wires (red and black) from the grinder motor winding and commutator using a screwdriver or pliers.

Step No. 3: Remove the old capacitor by pulling it out of the grinder housing with fingers or tools as necessary, then replace it with the new capacitor.

Step No. 4: Reconnect capacitor wires (red and black) to the grinder motor winding and commutator, making sure they’re tightly connected.

Step No. 5: Turn on the power to the bench grinder by plugging in the power cord from the wall outlet.

Start Capacitor Function for Bench Grinders

how to replace bench grinder capacitor

When replacing a start capacitor, it’s important to note that you may substitute one with a greater voltage rating. A 125V start capacitor is still acceptable for a bench grinder if the owner’s manual specifies one.

The inductive motor winding creates a phase shift that requires extra voltage space, hence the move was made. Also, having a little extra space in the voltage rating is seen as a protective measure because of the odd spikes in the electrical grid.

The only potential problem is if the bench grinder’s original capacitor has a higher voltage rating than the one you’re using.

Test of Bench Grinder’s Capacitor

To test a bench grinder capacitor, you will need a multimeter that can measure capacitance. Here are the steps:

  • Turn off and unplug the bench grinder to avoid electric shock.
  • Find the capacitor on the tool. It is usually a cylindrical object with two wires attached to it.
  • Discharge the capacitor by touching the two terminals with a screwdriver or other metal object.
  • Set the multimeter to measure capacitance values.
  • Connect the multimeter leads to the capacitor terminals, making sure the positive lead is connected to the positive terminal of the capacitor.
  • Read the capacitance value on the multimeter. It should be within the tolerance range shown on the capacitor label.
  • If the measured capacitance is outside the tolerance range, the capacitor is defective and needs to be replaced.

Wiring of Bench Grinder’s Capacitor

how to replace bench grinder capacitor

The bench grinder capacitor is a key component in providing the necessary starting torque to the grinder motor. The capacitor is usually in series with the motor and the wiring is usually straightforward.

A capacitor will have two terminals labeled positive (+) and negative (-). These terminals connect to the motor starter winding and the wiring diagram will show which terminal should go to which wire.

To wire the capacitor, first determine the motor start winding. This yarn will usually be labeled or colored differently than other yarns. After identifying the start winding wire, connect it to the positive (+) terminal of the capacitor. Then connect the negative (-) end of the capacitor to the other end of the start winding wire.

It is important to ensure that the connections are tight to avoid any electrical errors. Also, be sure to keep wires away from moving parts or sharp edges to prevent damage to wires or capacitors.

If you are unsure how to properly connect a capacitor, it is recommended that you seek the assistance of a qualified electrician to avoid any potential hazard.

If you want to know how to change the wheel of the bench grinder, then click to have a glance at it.

Frequently Asked Questions

What does a capacitor do in a bench grinder?

Capacitors are used in bench grinders to store energy and release it slowly, preventing the machine from overloading and causing damage. When the grinder is turned on, the capacitor charges up quickly and provides a burst of power to start the grinding process. This prevents the machine from sputtering and choking up on the active materials, which would cause it to stop working altogether.

How do you fix a vibrating bench grinder?

If you are experiencing problems with your bench grinder vibrating or shaking, there are a few things you can do to try to fix the static issues. First, make sure that the grinder is properly grounded by connecting it to an electrical outlet using the appropriate grounding cord. Second, adjust the angle of the blade using the adjusting wheel. Third, check the gears and shafts for debris or wear. Finally, clean the blades and shafts using fine-grade carbide grit sandpaper. If these measures do not resolve the problem, it may be necessary to replace the grinder altogether.

Why is my bench grinder making noise?

If you are hearing noise from your bench grinder, there are several possible reasons. The most common cause of noise from bench grinders is debris accumulation on the blades, which can cause the blades to overheat and make a lot of noise. To prevent this from happening, regularly clean the blades of your bench grinder with a wire brush or a steel wool pad. If the noise from your bench grinder is still not going away, it may be time to replace the blades.

Why is my bench grinder not working?

There are a few possible reasons why your bench grinder might not be working. First, make sure that the power is turned on and plugged into an outlet. Second, make sure that the bearings are lubricated and the motor is properly aligned. Third, check to see if any of the gears or blades are missing or broken. Fourth, make sure that the grinding wheel is properly aligned with the grinder head. Fifth, check to see if there is debris caught in the gears or blades, preventing them from spinning freely. Sixth, check to see if there is oil or grease on the grinding wheel or grinder head, which can cause them to become gummed up and unable to rotate freely.


Bench grinder capacitors are essential components in bench grinders and can fail for a variety of reasons. By following the steps provided in this guide, you can replace your capacitor and keep your machine running smoothly. By being proactive and testing your machine’s capacitors regularly, you can avoid problems down the road. This is about bench grinder capacitor replacement and helps keep machines running smoothly.

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