AC Motor Repair Process
- Electric Motor Inspection. Inspection is an critical step in evaluating the condition of a motor and establishing an...
- Cleaning and Baking Out Electric Motors. After a motor is inspected (and sometimes during the inspection process), it is...
- Electric Motor Repair Processes. The repair process itself depends on the AC motor diagnosis, what the...
Full Answer
How do you fix an electric motor?
How do you fix a overheating electric motor? A great way to do this is to use an overload relay. The role of relay is to protect the motor from overloading and overheating. If this occurs, the relay then deactivates the motor until the issue can be resolved. Some overload relays can also be developed into microprocessor systems.
Who rebuilds electric motors?
Electric Motor Repair, Rewinds, & Parts. Eurton Electric specializes in electric motor repair & rewinding. Whether it’s an armature, field coil, motor, stator, or anything else that requires winding, we can repair it! Family owned and operated since 1933, Eurton Electric is proud to have the employee expertise to repair and rebuild what other ...
Do electric cars use AC or DC?
While your electric car motor uses AC, the battery needs to receive its electricity in DC. A conversion from alternative to direct current, either onboard or outside the vehicle, is therefore required. Power from the grid is always AC.
Can an electric motor act like an electric generator?
Yes, of course, many electric motors can be used as generators. That has been done for more than 100 years. Until fairly recently historically speaking, elevators used that principle. They had a motor-generator (MG) set, consisting of a 3-phase induction motor which drove a DC generator which powered the DC elevator motor.
Can AC motor be repaired?
AC electric motor repair should be done by professionals, especially in larger machines, but small AC motor repairs can be done by anyone. You can identify the common problems using this AC electric motor guide, so you can understand the repairs needed.
How do I fix my AC motor?
0:158:38Replacing Condenser AC Fan Motor (Step by Step Instructions!) - YouTubeYouTubeStart of suggested clipEnd of suggested clipSo remove the panel. Once you remove the panel you'll go ahead. And just get access to the fan motorMoreSo remove the panel. Once you remove the panel you'll go ahead. And just get access to the fan motor and you'll want to follow the wires that are leading to the capacitor. And the contactor.
How do you rebuild an electric motor?
0:3224:43How to Rebuild an Electric AC Motor - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd show you guys how to test this and the repairs and the modifications. We can make to make itMoreAnd show you guys how to test this and the repairs and the modifications. We can make to make it last a bit longer and get it running again if it's not working.
What causes AC motor to stop working?
The most common cause of motor failure, and arguably the most difficult to overcome, is low resistance. Low resistance is caused by the degradation of the insulation of the windings due to conditions such as overheating, corrosion, or physical damage.
Can electric motors be repaired?
So long as the shell exists, a motor can be repaired and reconditioned. The key is to remember that eventually that motor will need a burnout and rewind before it is insulated again. Then, with proper maintenance and smart reconditioning, there is no limit to how many times you can have that motor repaired.
How do you test an AC electric motor?
Inspect the Motor Windings With a Multimeter To begin, set the multimeter to read ohms and then test the motor's wires and terminal. You should test the windings for a “short to ground” in the circuit and open or shorts in the windings.
Can you run an electric motor without a capacitor?
Answer: There are three common types of single-phase motors named capacitor motor, shaded pole motor and split phase motors. Shaded pole and split phase single-phase motors do not require a capacitor to run.
How much does it cost to have an electric motor rebuild?
Motor shop “A” quotes come back as follows: $1000.00 for a recondition. $2000.00 for a rewind. $200.00 to repair a housing.
What paint is used for electric motor?
Silicone paint has high heat resistance and can be used as a cover paint for H-class motor appliances.
How do I know if my AC motor is bad?
5 Signs Your AC Fan Motor Is BadThe cooling fans won't turn on.The fan turns on when the AC is running, but the blades rotate slowly.You can hear a rattling noise coming from the condenser unit.It smells like something's burning.Blown fuse.
What is the most common cause of motor failure?
Winding insulation breakdown and bearing wear are the two most common causes of motor failure, but those conditions arise for many different reasons....Shaft imbalanceDirt accumulation.Missing balance weights.Manufacturing variations.Uneven mass in motor windings and other wear-related factors.
What is the cleaning process for electric motors?
The cleaning process includes stators, rotors, and all other parts of a motor and will remove all contaminants and debris.
Why do electric motor repair shops charge inspection fees?
The purpose of an inspection fee is to cover the labor costs involved in the transport, testing, disassembly, diagnosis, and documentation that is all part of finding the source of your motor problems. Some electric motor repair shops may charge an inspection fee when you send your motor in for diagnosis but don’t have them repair it.
Can AC motors be repaired?
An AC motor repair isn’t complete until it has been tested, the results of those test have been compared to appropriate benchmarks, and everything has been carefully documented. When possible those tests should reproduce actual working conditions as closely as possible. For example, many shops will test a motor up to full speed, but not full voltage. Now, full voltage is needed to get accurate vibration readings that include magnetic vibration. This simply cannot be done at anything but full voltage. However, not all electric motor repairs shops have test panels that can handle the necessary KVA required to power the motor at full voltage and unloaded current.
Can you test a motor at full voltage?
Now, full voltage is needed to get accurate vibration readings that include magnetic vibration. This simply cannot be done at anything but full voltage. However, not all electric motor repairs shops have test panels that can handle the necessary KVA required to power the motor at full voltage and unloaded current.
Is it cheap to repair an AC motor?
AC motor repairs aren’t cheap, and you’ve probably discovered that already. Prices can vary widely when it comes to AC motor repair, but those prices depend heavily on what is wrong with the motor. For example, maybe the first time you had your motor repaired it was a bad bearing but the next time it fails there has been damage to the coils and it required a rewind. The rewind is going to cost significantly more than the bearing replacement. It also depends on things like repair time, method of repair, and whether the shop is EASA accredited.
Why does my Electrc motor overheat?
If your electrc motor is an "open" design you can see into the motor housing; look for clots of dust and oil that may be blocking the cooling fan and causing the motor to overheat; overheating can cause the motor's thermal overload switch to shut the motor off (and the switch may pop out waiting to cool-down and re-set).
Which way do electric motors run?
In short: check the motor label: uni-directional electric motors run just one way: clockwise (CW) or counterclockwise (CCW) but not both. Bi-directional & self-reversing electric motors run in either direction, CW or CCW. Some electric motors can start and run "backwards" following damage to the motor's start capacitor or windings.
What is a stator in a motor?
Electric motor stator: the stator consists is a device or core containing start and run windings (of copper wire) wound around a central core to create a magnetic field. Electric motor windings: the two windings are used to create an electrical field in the stator.
How many windings are in a single phase motor?
Reader comments on single phase & 3 Phase motors. Most single phase motors have two sets of windings. The main or primary windings are directly connected to the power lines while the motor in running. The second windings are usually thinner wires physically offset from the main windings inside the motor.
Why is a start switch necessary?
This feature is necessary because depending on the position in which the rotor stopped when the motor last turned off, the rotating electrical field created by the run winding can't start the motor.
How to diagnose a failed start winding?
A trained service technician may sometimes diagnose a failed start winding or failed start switch (centrifugal switch) by spinning the motor manually (potentially dangerous!). If the motor keeps running we suspect a bad start winding or bad start switch (see diagnostic table details
How to get more life out of a motor?
simply swap in a new start capacitor. That may give you some more life out of the motor.
What motor should I use for a shaded pole air conditioner?
If you have a shaded-pole air conditioner blower motor in your air handler, I recommend replacing it with a PSC motor. If you don’t know what that terminology means, the air conditioner technician should know.
What direction should a blower motor be?
Additionally, the motor direction, whether it be clockwise or counterclockwise. There are blower motors that are reversible with a simple wiring change.
How to keep air conditioner from freezing up?
Keep the blower wheel and the evaporator clean with a good clean filter and change it on a regular schedule. Dirty air filters can cause your air conditioner to freeze up. It is simply wise to keep a clean filter. It protects the motor and keeps it operating smoothly.
What is variable speed motor?
The variable-speed motor and can be found on most high SEER units . Variable speed motors are more expensive than standard blower fan motors or condenser fan motors. However, they are more efficient than conventional PSC motors and have better, although more sophisticated control.
Why does my air conditioner burn up?
That is common in the summer. High heat and constant use causes old (and some new) air conditioner blower motors to burn up. There are several different types of air conditioner motors. When dealing with anything electrical, the best replacement is an exact replacement. There is a contradiction to that phrase.
How much does a double shaft motor cost?
If your unit is equipped with a double shafted motor expect to pay up to $300.00 or more for a new motor. These double shafted motors are rare in residential units, but they do exist. Out of about a hundred motors in 2001, I only had one that was double shafted.
Can you reversibly change a blower motor?
There are blower motors that are reversible with a simple wiring change. The bracket, which is in the existing unit, may not be able to be reused. That will necessitate a new bracket that will mount the motor properly. Sometimes it also necessary to change the blower wheel.
How to remove a motor from a winding?
Unplug the motor from its power source. Access the connections between the power cord and the motor windings. Remove the junction box cover plate, if there is one. (Make some photos showing the connections so you can make them correctly again, if you need to take them apart.) If there is no junction box on the motor, remove the end of the motor where the power cord connects to the windings.
How does a capacitor start an electric motor?
Capacitor start electric motors use a starting coil and a capacitor to create an advancing magnetic field in the stator (outer frame of the motor with its coils). This advancing magnetic field gives the rotor something to chase, causing the rotor to spin. (For example, put a bar magnet on top of a glass table. Bring another bar magnet up to it from under the table. Move the magnet under the table. The magnet above the table chases the magnet under the table in a crude form of an electric motor. The advancing magnetic field in the stator replaces the movement of your hand under the table.) That starting coil will be destroyed if it remains powered up in the circuit more than a very few seconds. Most motors use a centrifugal switch to disconnect the starting winding from the circuit as soon as the motor shaft builds most of its speed.
How to check for open circuit?
You have checked for shorts. Now check for opens. Follow the wires as best you can. The starting windings use a thinner wire than the running windings. Use the Ohmmeter to check for breaks in both windings. The resistance on each winding will be relatively low, but the starting winding will show a little higher resistance. If one of the windings shows an open circuit, look closely at where the wires attach to a terminal or to a heavier wire. Such junctions are the most common places for an open junction to happen. (I once repaired a "dead" Dremel tool. There was no indication of an open circuit in any of the armature coils. But, the field coil showed an open circuit between the two terminal pins. I looked closely and saw a break where the coil wire attached to one of the terminal pins. I scraped enamel from the wire as best I could and made a solder bridge to the terminal pin. It was not a perfect solder joint, but the Dremel worked again.) If you are not able to find the break in the coil circuit and repair it, the motor will need to be rewound.
How long does it take for an electrolytic capacitor to dry out?
It is not uncommon for an electrolytic capacitor to dry out and fail in audio equipment after 20 years or less. But, replacing a start capacitor without first checking for shorted or open windings, an open reset, and a faulty centrifugal switch will not make your motor run, if the capacitor is not really your problem.
Why does my AC hum in summer?
The most common cause of HVAC failure during the hot summer is a motor capacitor. (Your air conditioner does not run, but just hums with a buzzing sound.) Knowing that, you can use what you find in this Instructable to check your system and replace the capacitor even before it fails.
How long is the start winding energized?
The graphic shows the circuit diagram for this type of motor. The start winding portion is energized for only a couple of seconds. Then the centrifugal switch locks out the components of the starting winding circuit. In the next steps tests will be done to eliminate probable causes.
Where is the capacitor on a motor?
Many motors have a domed cover on the outside of the motor, and the capacitor is under it . Motor capacitors are usually a cylinder with terminals on top. But, some capacitors in older motors may also be flat, like a short stack of 4 x 6 index cards.
How to balance an industrial motor?
Dynamic balancing of an industrial motor generally requires steps such as attaching a particular weight at a specific angle, taking detailed stationary measurements, starting the motor, bringing it to operational velocity and then using the measurements to inform the addition of permanent weights for proper balance and alignment.
What is the average failure rate for industrial motors?
Motor failures can occur for many reasons, and the average failure rate across industrial facilities is about 3.4% per unit per year, with a range of variation – relatively low, but breakdowns will inevitably occur.
What causes a brake pad to make a noise?
Sometimes, dust from the brake pads creeps into the bearing and soaks up all the lubrication, causing friction and noise. – Motor damage: A worn bearing can cause misalignments or put excessive strain on other motor components. These issues can lead to damage.
Why does a rotating rotor wobble?
If there is more weight on one side of the component, it will wobble as it rotates, causing failures due to vibration and instability. These problems get exponentially worse the higher speed the motor runs. Failures that can occur due to imbalance issues in rotating groups include the following:
How does a bearing heater work?
The new bearing goes into a bearing heater that will heat it to match the motor’s internal operating temperature. An induction magnet goes around it to spread out the heat, and a temperature probe reports the temperature. Heating the bearing helps it slide more easily along the shaft. If it gets stuck partway, the technician can use additional tools to press it into position.
Do industrial motors need paint?
Certain harsh, heavy-duty industrial environments require particular types of paint. Motors used at high temperatures, around caustic chemicals, in food service applications or outdoors in extreme weather may all need the protection of robust surface treatment. The exposed motors in wind turbines, for example, or on offshore drilling operations, are particularly vulnerable to abrasive conditions.
Can a bearing problem cause a breakdown?
These issues can lead to damage. – Catastrophic failure: Ultimately, if not addressed, a bearing problem can lead to a complete breakdown of the motor. A breakdown can halt productivity and necessitate time-consuming and expensive repairs, so you’ll want to try not to let a bearing issue reach this point.
AC DC Electric Motor Troubleshooting
With luck and good routine maintenance, you will get many years of performance from your AC and DC electrical motors.
11 Common AC induction motor problems and potential solutions
POSSIBLE CAUSE: Motor damaged and rotor is striking stator. Fan guard bent and contacting fan. // May be able to reassemble; otherwise, motor should be replaced. Replace fan guard.
6 Common DC electric motor problems and potential solutions
POSSIBLE CAUSE: Motor damaged and the fan guard is contacting the cooling fan. // Replace fan guard.
