However, if you’re motor isn’t working, use a multimeter to test it before deciding to replace it. With a multimeter set to low ohms (usually 200), test between each winding terminal and the metal casing of the motor. My electric motor only runs when it's not grounded. Stevens holds a General Certificate of Education from Chelmsford College of Further Education. Using Multimeter To Test Blower Motor Resistor. Fixed appliances should ideally be on their own circuit with the MCB sized to suit the appliance. An armature (pictured on right) has a continuous series of windings from each bar on the commutator, which loop around the iron stack teeth and connect to the next bar on the commutator. Locate the fuse for the blower motor in the owners/service manual. The function of the ignition coil in a leaf blower is the same as in every machine; it generates electric sparks that are used to … They are near the back and have two colored wires; usually red and black, attached to them. The motor windings are going to be very low resistance, I'll check one of mine and get back with you. However, if you’re motor isn’t working, use a multimeter to test it before deciding to replace it. At first look, this may seem to be an oxymoron, but it really isn't. There are few, if any, serviceable parts in small electric motors, and generally it’s less expensive to buy a replacement rather than attempt a repair. Beyond just issues with the capacitor’s multimeter readings, it’s possible to observe problems with the unit visually. You need to replace the wiring before your motor will work. How can I check for the cause? Values greater than this indicate a potential problem and values significantly greater than this indicate the winding has failed opened. To check an electric motor to see why it failed, look at the outside for signs of debris that has been sucked into the motor windings, as well as broken mounting holes or feet, and darkened paint that could indicate excessive heat. BTMETER BT-770K Auto Ranging Automotive Multimeter for Dwell Angle Pulse Width Tach Temperature Duty Cycle Voltage Current Resistance Test 4.3 out of 5 stars 24 $49.99 $ 49 . If you want to test a blower motor capacitor of yours, make sure that you discharge it with a screwdriver before you begin the test. I'd hate to replace the blower motor only to find out it's the switch or something else. Do the following with the motor disconnected. Turn on the motor so you can test if electricity is getting to the armature. If you don’t get a measurement, then it means power isn’t reaching the motor, so it may not be the motor that’s faulty. 2. Touch each of the meter's probes to one terminal each. If it has bronze sleeve bearings (rather than ball bearings) the bearings are out of oil and have seized up. Locate the two terminals and place the sensors from the end of the multimeter wires onto the two terminals as before: red on the terminal that has the red wire attached and black on the terminal that has the black wire attached. Loops are either single or parallel conductors (wires), and can circle any number of times around the stack teeth (called turns in a coil). Many digital meters do not offer the ability to zero, so skip the "zeroing" information above if yours is a digital meter. When a motor fails, it is often difficult to see why it failed just by looking at it. The blower motor resistor can be easily tested with a set of simple multimeter resistance tests (especially since it's very accessible). (240 volt output cannot be tested on a 110 volt appliance.) CASE 2: All 3 terminals had 12 Volts where indicated in the test steps. You can find that by checking the ohms between the motor terminals, if shorted or not . Keep the multi-meter set for 30,000-ohms and touch one test lead to one terminal and the other to another terminal. Now check the ground connection. Look at the label on the electric motor to determine the voltage it needs to operate. If not, they could be skipping across high spots on the commutator. We use cookies to make wikiHow great. It is not that uncommon for a motor's windings to be both "open" and "shorted" at the same time. References. If your car’s blower has only 4 or 5 different speed settings, it likely uses a simple electric resistor to control the fan’s speed. Turn the rotors and push and pull the shaft to test the bearings; if the rotors move smoothly and there is little to no movement in the shaft, the bearings are probably fine. Place the copper sensors running from the multimeter onto the metal terminals on the small electric motor. Turn on the power unit that supplies electricity to the electric motor. Drip-proof motors can be installed in damp or wet locations, so long as they are installed in such a way that water (and other liquids) can not enter due to gravity and must not be subjected to a stream of water (or other liquids) directed at or in it. Placing the test probes on the capacitor terminals, the resistance should start low, and gradually increase as the small voltage supplied by the meter's battery gradually charges the capacitor. Take the black multimeter standard test lead and touch the white wire with it. 2001, 2002, 2003, 2004 Dodge Dakota, Durango. Dec 23 2007, 11:38 PM. Type — describes if frame is open, drip proof, total enclosed fan cooled, etc. Anyone know the best trouble shooting method or order I should go in to find the problem before I take apart the whole heater housing to get to the blower motor and replace it. How to test a blower motor capacitor with the multimeter? % of people told us that this article helped them. Small electric motors operate a wide variety of electrical devices, such as remote-control models, children’s railroad sets and computers. My table saw motor has an inconspicuous built in circuit breaker button that tripped on low voltage/high load. Locate the retainer clip in the center of the blower wheel. It’s possible the problem could be the wring or the power source and not the electric motor. The winding continues to loop all the way around the armature in the same manner. http://www.uesystems.com/news/the-50-failure-modes-of-electric-motors, https://www.vfds.com/blog/how-to-read-a-motor-nameplate, https://www.fluke.com/en-us/learn/best-practices/motors-and-drives/troubleshooting-motor-bearing-wear, https://www.machinedesign.com/motorsdrives/trouble-shooting-bearing-currents, https://www.accelix.com/community/preventive-maintenance/typical-causes-of-electric-motor-winding-failures-and-how-to-prevent-them/, https://www.groschopp.com/how-to-check-a-motor-armature/, http://www.tigertek.com/servo-motor-resources/check-spindle-motor-windings.html, https://sciencing.com/troubleshoot-electric-motor-capacitor-problem-8001821.html, https://motorimpex.ua/files/downloads/MPFiltri_LMG.pdf, https://www.powertransmissionworld.com/is-your-electric-motor-trying-to-tell-you-something/, https://electrical-engineering-portal.com/7-most-common-motor-enclosure-types-defined-by-nema-standards, consider supporting our work with a contribution to wikiHow, Darkened paint in the middle of the motor (indicating excessive heat), Evidence of dirt and other foreign matter having been pulled into the motor windings through openings in the housing, Manufacturer's Name — the name of the company the made the motor, Model and Serial Number — information that identifies your particular motor, RPM — the number of revolutions the rotor makes in one minute, Horsepower — how much work it can perform, Wiring diagram — how to connect for different voltages, speeds and direction of rotation, Frame Style — physical dimensions and mounting pattern. The resistor tested at 197.6 ohms. If the motor is direct-drive these numbers can be difficult to read. For demonstration purposes, I decided to use my meter to actually test a 200 K ohm resistor. 99 If the motor itself has developed a fault, the fault may be a burnt wire or connection, a winding failure includin… How to test. Place one probe on the bare metal housing of the motor. A motor with high resistance will not run - or not run with speed control (as is the case when a 3-phase motor winding opens while running). Test the fuse, with the ignition key on, using the 12-volt test light. A quick check-out can be done with a simple ohm meter, but there's a lot more information to collect and weigh before actually putting it to use. I was runing a 240v 2kw motor off a faulty generator which I now know was producing less than 240v. Multimeter Test. Check the multimeter measurement. TEFC motors on the other hand, can be used in all the previously mentioned areas but must not be submerged unless designed specifically for the purpose. With the design efficiency; ... Do not do an under load test on blower capacitors due to the risk of the meter leads around a spinning blower wheel. Place the metal prong on the end of the red wire from the multimeter onto the red wire that connects to one of the brushes. The heater blower motor is located behind the glove compartment of your vehicle. If the ampere reading is within the range you set on your multimeter, the AC motor is drawing the correct amperage. The fuse is fine. How do I check and find out with a multi-meter whether a motor is faulty or not? It should give you a digital reading, ideally within 6 percent of the manufacturer specifications for the capacitor. It’s possible the problem could be the wring or the power source and not the electric motor. If it's a single-phase type, you just need to move L1 (the only phase) between the 02 leads of the capacitor. One of them is probably open. Many blower resistors control current to the blower motor in all speeds except high. Minimum test value of motor insulation resistance is 1 Meg Ohm (1 MΩ). If it stays shorted or does not rise, there is probably an issue with the capacitor and may need to be replaced. ", not all motors are the same. Another possibility is that the driven load is jammed, binding or mismatched. You need to find the bare part of the wire that connects to brush. Turn off the motor. If it's below the range, get your motor checked as … MCBs should be of type C or D to allow for inrush current, and the Z ratings of the circuit must be below the specified threshold in your locality for the rating of the overcurrent device. To test continuity, all you have to do is stick 2 terminals on your multimeter against 2 ends of an electrical current.