Bench grinder buzzes

WEN is a leading power tool manufacturer. They produce many kinds of power tools. This grinder is just another quality product from them. WEN 4276 bench grinder has got 2.1 ampere motors that can run in a 3450 RPM without load.

Ah, the start winding is not operating. When you turn the motor by hand. When the motor speeds up, do you hear a click sound? This is the start winding switch working. There might be a capacitor that is wired in with this switch that is used to start the grinder. If this capacitor is fried, the motor will not start. If the switch is shot, also the motor will not start. There could also be a wire or connector in this part of the motor that is not connected, or fried and not making contact. These are a few things to look for.

Unless the motor is a brush type universal unit, there is commonly no way to change the speed of an induction motor. There are AC motor speed control units available, but cost more than the grinder as they change the frequency as well as the voltage. There are speed controllable grinders available that use brushes so that simple electronics can control speed. Hope this helps!

Hi there, with out seeing it I`d say your brushes are gone and ceasing. I hope this solves your problem.

There is a short internally in the motor. IMO not worth repairing, new bench grinders are pretty inexpensive.

The motor has a high spot on the armature causing the motor to stop rotating. The humming noise is the fields full of current which is making the armature to react to make this noise. For the money purchase a new bench grinder which is an easier fix than dumping money into your old one here

Hi Chip , have you tried !!carefully!! turning the grinding wheels whilst the grinder is powered up and humming and does this start the machine , if it does your motor start capacitor ( a cylinder/tube with 2 wires or connectors on it ) will be deffective or the leads might have became detached from it , a replacement capacitor is quite cheap but you must replace it with the exact one ( a motor start/run capacitor of the correct Mfd or uF rating typically 30 uF/Mfd and at the correct voltage 110/220V )
if this dosent fix your problem most likely your motor start windings in the motor field coils are burnt out and the grinder is uneconomical to repair .
hope this helps .

LIKELY the capacitor which is usually in the base is bad.

The capacitor shifts the phase angle in one of the two windings which creates a pseudo rotating field to start rotation.

hi it is an induction motor so ANY friction will stop it from starting DISSCONNECT check for any tightness when you turn it over by hand if all is well the condensor has failed hope this helps merlinv12

if this is a cap start motor and not a centrifugal start run motor then bad cap is good place to start