Hello and welcome to Grizzly's motor troubleshooting and repair video. My name is
Kent and this is one in a series of how-to videos we're producing making it easier for our customers
to upgrade and maintain their Grizzly equipment. This is Shawn, an engineer here at Grizzly,
and together we're going to show you step by step how to easily check some common motor components
and how to adjust or replace them if needed. We recommend you watch this entire video and
contact our technical support at 570-546-6966 if you have any questions or need further assistance.
Start capacitors are connected to the start windings in single phase induction motors and
provide an artificial second electrical phase to allow starting. They do this by storing and
releasing an electric charge that is out of phase with the main or run windings, which creates a
rotating magnetic field that starts the motor turning. This is the centrifugal switch. After
the motor starts and reaches operating speed, the centrifugal switch disengages and the capacitor is
no longer connected to the circuit, because it is only needed for starting. When a capacitor fails,
or the centrifugal switch shifts out of adjustment, the motor may hum without starting,
start sluggishly, or trip a circuit breaker. The following steps will take you through
troubleshooting these components. Capacitor inspection and testing. Disconnect the machine
from the power supply. Use caution when working with capacitors. They can store a significant
electrical charge even after the machine has been turned off. To avoid getting shocked let
the machine sit for at least five to ten minutes to allow the capacitor to naturally discharge
before performing any work. Motor capacitors are typically located outside the motor housing,
underneath a half-round cover. To access, simply remove the two screws that hold the
cover on and lift the cover off. As an extra precaution against being shocked, short the
leads on the capacitor with an insulated or wood handle driver. Before touching any bare wires,
the screwdriver must contact both leads at the same time. Be careful as there is a small chance
for an arc or spark when this is done. Make sure there are no flammable materials nearby and that
you're in a safe environment where a spark would not cause a fire or an explosion. Now inspect the
capacitor closely for signs of damage, such as bulging, bursting, or leaking oil. If you see any
of these signs, the capacitor must be replaced. If there are no visible signs of damage, test the
capacitor with an analog or a digital multimeter. The meter should be set to the ohm setting. Place
the tester leads on the capacitor terminals. The multimeter scale should start at zero and
then rise to infinity. Here is how it looks on an analogue type meter. Here is what you should see
on a digital type meter. If there is no reading, or the reading fluctuates up and down, then the
capacitor is dead or it has an internal short and must be replaced. The replacement capacitor
must have the same microfarad value and a voltage rating equal to or higher than the original. Next
we are going to look at centrifugal switch and contact plate inspection and adjustment. Over
time the centrifugal switch may shift out of adjustment, which can cause the start capacitor
to fail. To check the centrifugal switch, first disconnect the machine from the power supply.
Remove the fan cover from the end of the motor then loosen the retaining screw and remove the
fan from the motor shaft. Remove the dust cover, if there is one, loosen the retaining screw on the
centrifugal switch and slide the switch off the end of the shaft. Locate the points on the contact
plate and make sure they are in the open position. If they are closed, bend the circular spring flat
so the points no longer contact one another. If the points are welded shut, then the contact
plate must be replaced. Over time, the points on the contact plate can develop a blackish carbon
buildup due to the capacitor discharge during the startup phase. This is normal and will not affect
startup. Look closely at the surface of the points for signs of pitting. Light pitting can be gently
sanded with some 400 grit sandpaper. But larger deformities on the surface of the points will
cause an unusable condition and potential arcing. If excessive pitting is detected, the contact
plate should be replaced. Now that the quality of the contact points has been verified, you can
reinstall the contact plate. Place the centrifugal switch back on to the motor shaft. Make sure the
orientation of the switch is correct so the collar and retaining screw face towards the fan end of
the motor. Slide the body of the centrifugal switch further onto the shaft until you see
the contact points barely touch each other. Temporarily secure the collar with the retaining
screw and mark the motor shaft with a felt-tip pen just above the collar. Now loosen the screw
on the collar and adjust the centrifugal switch further onto the shaft until it is 1/16 of an
inch below the mark on the shaft. Then tighten the retaining screw on the collar. If the switch is
adjusted too far past the mark on the motor shaft, the contact points may not open after the motor
starts. This leads to capacitor failure, and the next time the start switch is turned on, the motor
will not start. Please use care when making this adjustment to avoid damaging the capacitor. Once
you are done, replace the remaining components in the opposite order they were removed. Test run.
Once assembly is complete and adjustments made to your satisfaction, you are ready to test run the
machine. Make sure the power switch is off then plug the power cord in. When you turn the power
switch on, make sure your finger is poised over the off button just in case there's a problem. The
motor should start and run smoothly. Well that's it for this video. Hope we were able to help you.