If your furnace requires you to “reset” before it operates, it’s likely that it shut itself down for safety reasons. I have an old 25-inch, 3-blade industial fan. Does it run? This issue is a fairly common one where repairs are concerned, and knowing the signs might help you out in the future! Because this is an electric motor we may forget that it needs ventilation for it to function efficiently. Poor voltage conditions are frequent and can be caused by a variety of reasons. What can you do yourself? Jerry Kelly is here for you during this crisis, Benefits of HVAC Replacement for Missouri Homes. Voltage distortion was poor due to a previously unidentified silicon controller rectifier defect in the power supply. If there is no power you want to check the circuit breaker first to see if it is tripped. If a motor is started off at a bad current value, it starts operating in a much warmer condition than the design temperature. Having then removed the protective cover from the motor to investigate it became apparent that the motor was too hot to touch with my bare hand. In industrial applications, perfect voltage conditions are rare. Your blower motor can give you some very clear signs of overheating, including: The initial cause of an overheat can be pretty diverse. 1. Leading standardization organizations have concluded that 30 percent of motor failures are attributed to insulation failure and 60 percent of these are caused by overheating. There are electrical components and sharp parts in your system, and poking around can be very hazardous to your health! The motor will start when it has cooled down, then stops running as described above. If you observe this we suggest that to avoid damage you turn off the system while waiting for repairs. Submit Your Quote Selected Products We have many homeowners call us mentioning humming and other odd sounds. All of Kelly’s technicians have been extremely professional and knowledgeable. The winding insulation … This scenario shows a NEMA derating of 0.7 which allows the motor to be operated at only 70 percent output. Maximum number of starts and stops for line-operated motors as a function of their rating and speed. The fundamental reason usually is excessive heat. Alex J did a fantastic job installing and explaining our new heater. This justifies the need for accurate knowledge of operating load level. Table 1. They are AC Motor Fan and DC Motor Fan. This generates excessive heat, causing an overheat and the humming. Limiting the frequency of startup, the most stressful portion of motor operation, is highly important. If the fan blades move a little or it starts to turn, the motor is probably still good. 1 shows the NEMA derating curve for percentage of unbalance. Fig. Self-starting DC motor inside the motor housing of the fan helps these blades to oscillate 360° until the fan is turned OFF. If the circuit breaker controlling the fan tripped when the smell was initially detected then an electrical fault is the likely cause. 2. Many problems occur with electric motors. If it’s not getting it, it’ll wear out eventually. Maintenance experts agree that excessive heat causes rapid deterioration of motor winding insulation. So, what happens if we operate a motor above its design temperature? The experts at Jerry Kelly Heating & Air Conditioning carry years of experience, offering the absolute best in diagnostics, repair, maintenance, and replacement. The frequent use of variable frequency drives (VFDs) can result in detrimental effects to electric motors because of the condition of power in manufacturing facilities. We Respond Quickly & Fix it Right The 1st Time! Does the fan start and run at each speed? Preventive maintenance practices frequently limit on-line electrical measurements to interpreting current levels. Could be a production fault requiring a recall. Signs of an Overheating Blower Motor. Hot enough to throw a pan over and start cooking bacon 'n' eggs. Overheating also occurs when an electric motor is forced to operate in a high temperature environment. Email. found a bad run cap on fan in furnace . A higher service factor signifies the motor’s capability for overload for short periods of time, not higher steady state operating capabilities. The motor is either hidden in the fan's center hub or extends behind it. (When I say motor, I mean the housing over the motor.) There are typically five main reasons for overheating—overload, poor power condition, high effective service factor, frequent stops and starts, and environmental reasons. If it is starting and getting to full speed with the capacitor but then getting hot after a little while it would be the centrifugal switch. I turned it off and noticed a smell, the familiar smell of electrical equipment going 'poof'. A = Maximum number of starts/hr C = Minimum rest or off time in seconds between starts, © 2020 Efficient Plant. While important, this method is inconclusive in identifying failures caused by excessive winding heat. 4 Stars & Up & Up; 3 Stars & Up & Up; 2 Stars & Up & Up; 1 Star & Up & Up; Brand. Put it back up and wire it. The chief enemy of an electric motor's insulation system is heat, so you want to be sure the motor stays within limits for long winding life. The hot topic of motor temperature. We do not recommend you go looking for the blower motor. NEMA derating curve. Instead of time here spend the time putting it on the manufacturer to fix. Under full load conditions, this is the difference between life and death to a motor. Motor windings do not build up resistance to current until the motor is actually turning. What Is Causing the Motor on an Electric Fan to Slow Down and Stop?. Also, over time, excessive heat occurs. MT. Furnace cycles off and refuses to restart. Dirt and dust buildup. Generally speaking, your furnace was built to withstand. For example at a coal-fired power plant in the United States, a 7000 hp 6.6kV motor was running with only 7 percent overcurrent, but an 8 percent overvoltage. Customer Review. If you’re looking for furnace services in St. Louis that are guaranteed to meet your needs, contact us today online! A common mistake is made in operating at an overvoltage to reduce the stator current and to reduce the introduction of heat. They’re hardy, sound machines that require little in the way of repair (provided they are properly maintained!). The resulting NEMA derating factor of 0.85 results in an effective service factor of 1.17, which signaled an alarm condition. The motor may fail due to disrepair or a lack of appropriate maintenance. Losses, not current levels alone, are the true source of heat. Like any moving part, the motor occasionally needs some TLC. Fig. mismatched a coil and condenser ,but cooling Including those associated with lubrication and voltage spikes. The blower motor is responsible for the process of cycling air from your furnace, to the vents throughout your home. This figure is also defined in the formula. Effective service factor T he key to finding the most frequent causes of overheating is accuracy in estimating load level. Most electric motors used in industrial settings are Class B or Class F designs. Universal Bathroom Vent Fan Motor Replacement Electric Motors Kit Compatible with Nutone Broan 50CFM 120V. I gave it a little push and then it came on and the car went back down to normal operating temp. The motor that I removed was the same but I don't know how long it was in this fan. 2 shows the voltage that a VFD, running at almost a 6-pulse mode, will send to the motor. Take a Look at Table 1 – Insulation Class. This can be identified by looking at only currents and voltages. NEMA specifies which load level is permitted for poor voltage conditions. Many well-documented cases of recurring motor failure were addressed by increasing the horsepower rating of the motor which shortened the time between failures. Take it down and clean all the screens and holes with compressed air. Hard to know with something that old though. Or maybe your furnace regularly kicks off when it shouldn’t! So, how hot is too hot? The fan uses a relay in the fuse relay box under the hood. Capacitors are electric devices that get an electric motor running at start-up or that help keep a motor running once it has started. It runs fine, but after 5 minutes of use, usually immediately, the motor gets very hot. The problem could lie with an overheating blower motor. If you don’t hear anything, put your ear up to the middle of the case behind the blades. Electrical; Engines; Accessories/Keys; How to Connect a Radiator Fan to a Hot Wire by Don Bowman . See 'Ceiling Fan Troubleshooting' or 'Electrical Repair' if this is not your problem. 99. 2. This Instructable concerns a triage procedure for getting your capacitor start motor running again in a series of easy and logical steps. Noticing some odd sounds coming from your furnace? For us, this is plenty of reason to suspect an overheating blower motor. Fan motors get hot and rely upon cooling by the air they circulate. On-line testing can ensure full compliance to professional standards. Increases in the temperature of an electric motor reduce its lifespan. Thank you, Korey T., for restoring our heat! Two identical applications had undergone unscheduled outages in the previous 12 months. A load error of more than 10 percent can be introduced by relying on stator current readings to access probable load and heat levels. More Buying Choices $20.13 (2 used & new offers) Endurance Pro Universal Bathroom Vent Fan Motor Complete Kit Replacement for C01575, 50 CFM, 120V. The key is to closely monitor the number of starts—hourly for small or medium motors and daily for larger motors. However, the root cause of the failure was actually the frequency of starts and stops. Extreme distortion with a slow switching VFD (50 hp, 4-pole). I was sitting at a drive-thru earlier and I noticed my heat hand started to move as I sat there longer. DC motor ceiling fan can rotate in both clockwise and anticlockwise directions. 4.6 out of 5 stars 1,456. A second terminal becomes hot only when the key is on. Test to standards Bearing and winding failures are the most common motor failures. We have had a great experience with Jerry Kelly every time we have needed service. Chemical abrasive substances in the air, wet operation, and high altitude operation are a few common environmental stresses. It can be used in identifying reasons for failure in operations that do not comply with standards by including these standards in long-term unsupervised monitoring operations. These losses are a destructive factor to windings and a significant reason for bearing damage. If it isn’t, it soon will be. Fig. Your blower motor can give you some very clear signs of overheating, including: A “hot” or burning smell from vents in the home. I pulled over in the parking lot and let it idle and I did not see my radiator fan come on at all. It only gets hot enough that you’re glad to put your hands on it on a frosty morning. A power transformer will ALSO not get warm on no load. Regardless of nameplate service factor, any motor operating above 1.0 service factor is under stress. We do not recommend you go looking for the blower motor. Automated assessment is necessary to effectively ensure motor health. Use a non contact voltage tester to see if you have any power at the switch. If you suspect your blower motor is overheating, or any other aspect of your HVAC system is acting in a way it shouldn’t, call on our experts today! It’s inevitable, and all you can really do is know who to call, and what you’re looking for. Dust and grime building up around the motor can make the blower unable to vent itself, building heat over time. I question the need for a user to modify a manufacture or design fault. Often motors overheat because they have power to start, but something is preventing them from operating. Power condition Electric motors in manufacturing plants generally need to be derated because of poor power conditions in order to maximize their useful life. Turn your fan on to make sure that the motor works. Mophorn; A.O. The relay has four terminals--one that is hot all the time, even with the key off. The electric cooling fan uses a direct current (DC) electric motor with a thermo switch, module or computer control to turn it on or off, depending on coolant temperature or AC operating condition. I tried to call Fasco and they could not tell me any running temperature specs. I did not truly measure the temperature but I cannot touch the motor while it is running or I will get burned... seems like more than 174 degrees farenheit to me. Casing is hot and that is radiating some of it. Cultural Change For Success: A Lumber Mill’s... Understanding Shaft Alignment: Identical Machines. This causes the rate at which heat can be conducted to reduce at an alarming rate. An electric motor generally runs maintenance-free for many years. Ensure power to the unit is turned off. For example, if a 100 hp motor has an unbalance factor of 3 percent, the motor should be derated to 0.88 or 88 percent of capacity, 88 hp. According to the derating curve, the higher the level of unbalance, the lower the acceptable level of steady state load. Fig. Severe distortions are evident. On a large cast iron, totally enclosed, fan cooled (IP 54) motor, for instance, the surface may be 20 to 25 C cooler than the winding hot spot, but only 10 to 15 C cooler on a rolled steel frame motor, where the surface is much closer to the winding. There are electrical components and sharp parts in your system, and poking around can be very hazardous to your health! Don't. This explains why these motors were failing. The end spindles on the armature are seated between bearings, which enable the motor to rotate smoothly and quietly. Stop the blades, set the speed to low, and turn on. Poor air flow? NEMA MG-1 Sections II and IV specify what voltage quality, as a function of balance and distortion, allows what level of percentage load. It's got a Dayton LR-something 1/4 horsepower motor on it. If you’ve ever cleaned out your computer, or another similar piece of equipment, you’ll know what we’re talking about! Namely, overheating, likely localized around the blower motor. Get it as soon as Fri, Feb 19. Seriously though, electrics is not my area but if a motor is too hot to touch in such a short space of time it’s probably on it’s last legs. Smith ; AO Smith; Makermotor; EUDAX; Grizzly Industrial; PEMS; LMioEtool; Marathon Electric; LEESON; Price. Frequent starts and stops Table 1 displays the maximum number of starts and stops for line-operated motors as a function of their rating and speed. 6 reasons your motor may be overheating: 1. motor size, 2. ambient temps, 3. duty cycle, 4. voltage supply, 5. altitude, 6. ventilation holes. See below to determine if this is your problem. Component failure. Sometimes time is the biggest threat to your furnace system. 3. A “hot” or burning smell from vents in the home. There are typically five main reasons for overheating—overload, poor power condition, high effective service factor, frequent stops and starts, and environmental reasons. You have an electric motor designed to run on alternating current, but it does not run. Articles have been published stating that a significant cause of bearing deterioration is overheating. The best way to ensure successful preventive maintenance and monitoring is to test according to NEMA and other professional standards. This component can be seen by use of the blower access panel usually located on the side of your unit. All Rights Reserved, NEC 2020 Enhances Service Entrance Safety, SPONSORED: Three Ways to Increase Efficiency in the New Year, COVID-19 Best Practices Keep Workers Safe, A Calibration Service May Be Your Solution, Augmented Reality Delivers Maintenance Offering for Italian OEM, Provide Career Paths For Multiple Locations, Apache PowerCleat Belting from Motion Industries, Managing Availability for Improved Bottom-Line Results. Common issues include: Don’t allow your furnace to become a source of stress! Stator current is frequently used to measure load level, but load level can easily be masked by an overvoltage condition. You may hear it humming or observe that it's getting hot. The reason you have a start winding and a run winding all has to do with the fact that single phase power does not produce a rotating magnetic field. Loud humming and other unusual noises. Under $25; $25 to $50; $50 to $100; $100 to $200; $200 & Above $ $ Go Deals. Various possible defects could cause an electric motor to jam or bind, such as loose mounts, bad bearings, loose couplings, defects in the driven-assembly or part. If the capacitor has failed the symptom is that the motor won't start. 1. The common rule states that insulation life is cut in half for every 10 C of additional heat to the windings. If a motor begins to overheat, it can cause damage to the motor’s internals, shortening its life. Do this for each speed. The distorted currents are the motor’s reaction to poor power condition. $21.99 $ 21. The reason a stalled fan motor gets hot is largely down to the cheapness of its construction, and the losses in the iron and copper tolerated when the air is moving through the motor, but not when its at stall. This symptom is often coupled with the furnace shutting off … Replacing a condenser fan motor is a fairly simple task that most reasonable handy homeowners can complete themselves with just a little bit of know-how in just a few simple steps: Gather the correct replacement parts and required tools. The blower may be simply too old, in which case it may need to be replaced. FREE Shipping on orders over $25 shipped by Amazon . Fan motor is too hot, 4 tips to reduce heat, increase durability for all electric fans when used. We provide the absolute best furnace services in St. Louis, and we guarantee your satisfaction! A motor that cannot breathe is a motor that cannot perform. Plug your fan in and turn it on to the highest power setting. Environmental conditions Thermography is frequently used to determine the conditions where electric motors are being used. If the blower motor is old enough to fail, it’s likely your system is the same age or older, meaning you’re getting poor efficiency and lackluster performance. Resolved the problem so we could stay warm. ©2021 Jerry Kelly Heating & Air Conditioning, Terms of Service | Privacy Policy | Sitemap | Design & Marketing by LeadsNearby. Thanks for all your comments, truly appreciated. However, after looking at the true load to the motor, an overload of nearly 20 percent was discovered. Two kinds of ceiling fans are available in the market depending on the motor type. I would highly recommend them. In this instance, we would recommend considering a complete furnace replacement. On-line monitoring tools capable of accurately calculating operating load ensure plant operation within appropriate limits. The repair for each of these three motors ran into the hundreds of thousands of dollars. Mike and Heath came out on a very cold Saturday and provided professional and friendly service. A mild overload was identified by examining the stator current of this motor. In another example, data gathered using a dynamometer showed a 300 hp motor under test was running a nearly full load, 99.7 percent. As an example, if a motor that would normally last 20 years in regular service is running 40 C above rated temperature, the motor would have a life of about 1 year. You should disconnect the fan immediately. Poor cooling due to high ambient temperature, clogged ducts, etc., are typical examples of nonelectrically induced temperature stress on both the motor and insulation system. A general rule of thumb to consider is that for every 10°C above design temperature, the life of the insulation system is cut in half. We appreciate your prompt and professional service! Your description sounds like there is a small amount of current getting to the motor. Only accurate load level calculations can give reliable measurements of excessive losses and overheating in the motor. As stated before, the generated heat is wasted energy being burned off before it can … Age. It is very important that the motors should be matched with their ideal current values. Overload conditions. It has been shown that for motors ranging from 10-200 hp, operating at a 10 percent overvoltage would typically decrease losses by only 1-3 percent. For big industrial fans, three-phase asynchronous motors are commonly used, placed near the fan, and driving it through a belt and pulleys. On older fan circuits, the thermostatic switch connects to battery power on one side, and to the fan motor on the other. It has only one moving part, the armature, which has one or more wire windings wound around the central section. Tools & Home Improvement; Electrical Equipment; Electric Motors; Electric Fan Motors; Avg. Bearing that in mind, eventually, all furnaces will encounter an issue every now and then. It continued to move and I turned my car off. If pressing the reset button starts the motor but it runs hot or noisy see the motor noise diagnostic article at right. Ernesto J. Wiedenbrug, Ph.D., is an R&D engineer at Baker Instrument Co., 4812 McMurry Ave., Fort Collins, CO 80525; telephone (970) 282-1200. The formula for calculating effective service factor is: Effective service factor provides predictive maintenance professionals a solid conclusion of stress on any particular motor load application. Faulty electrical wiring can cause a burning smell. The area where electric motors … Even though the motor current may vary when applying overvoltages, the excessive damaging heat in the motor will not improve. How to Replace a Condenser Fan Motor. A radiator fan requires an average of 15 amps to operate. This symptom is often coupled with the furnace shutting off completely. Best advice would be to hire a licensed electrician to check it out for you. Overload conditions Stator current is frequently used to measure load level, but load level can easily be masked by an overvoltage condition. If the fan won't run at all it is likely not getting power. An internal combustion engine requires fresh air to aid in firing its cylinders; whereas an electric motor requires air to keep it within an optimal operational temperature. Standalone fans are usually powered by an electric motors, often attached directly to the motor's output, with no gears or belts.