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What happens when an electrical motor dies?
If I set up an exhaust fan in the crawlspace that runs non stop, eventually
the motor would wear out and fail. Would it go up in flame? Or are all motors used in the usa required to shutdown gracefully? Alot of fans/motors are used in commercial applications. I can't imagine them going up in flames at the end of their lives. |
What happens when an electrical motor dies?
many have a thermal fuse built into the motor, if it gets too hot the thermal fuse blows, cutting off power
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What happens when an electrical motor dies?
On 10/1/2013 10:06 PM, bob wrote:
If I set up an exhaust fan in the crawlspace that runs non stop, eventually the motor would wear out and fail. Would it go up in flame? Or are all motors used in the usa required to shutdown gracefully? Alot of fans/motors are used in commercial applications. I can't imagine them going up in flames at the end of their lives. Mine have either broken a wire, and gone open circuit. Or, the bearings dry out, and they over heat. Often, that causes them to break a wire. I'm sure motor fires have happened, but I can't say I know of one in my life. .. Christopher A. Young Learn about Jesus www.lds.org .. |
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Take a look at the electrical schematic for an induction electric motor: http://img.bhs4.com/a5/4/a54261670cf...a9a0_large.jpg This one is a capacitor start motor, but a split phase motor's schamatic would be exactly the same, except that it wouldn't have a capacitor. You have a Main winding and a start winding. The start winding is taken out of the circuit as the motor comes up to speed. If that were a DC circuit, you'd have a dead short through the main winding. The only reason the current through the stator in a real AC electric motor doesn't become excessive is that the main winding sets up an electric field through which the rotor windings spin. That action creates a current in the rotor windings, and the current in the rotor windings creates a magnetic field that opposes the current through the stator windings. This is why electric motor only draw a lot of current when they're starting. Once they're up to speed, the running current is actually quite low, making them highly efficient mechanically. But, if you were to grab onto the rotor and prevent it from turning, you wouldn't have the electrical current generated in the rotor windings and there'd be no opposition to the current flow through the main winding, and the result would be that the current through the main winding would act like a dead short and quickly exceed the amperage of the fuse or circuit breaker that motor is on, shutting down electrical power to the circuit. The motor would only go up in flames if it wasn't fused down to a lower amperage. If it were the convection fan motor in a convection oven that was on a 220 volt 50 amp circuit, then there could be 50 amps going through the stator, in which case it would probably get so hot the flammable parts inside it would probably catch fire. I've never had a convection oven, but I expect the motor of the convection fan has it's own fuse or fusible link so that if current through that stator got excessive, the fuse or fusible link would burn out. Otherwise, it'd be kinda dangerous and a potential fire hazard. |
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So, if you use a blower driven by a Baldor motor, and you make a point of rebuilding that motor every 40 years, it'll outlast your grandkids' grandkids. Baldor Electric Company, a leader in energy efficient electric motors, linear motors and adjustable speed drives industry |
What happens when an electrical motor dies?
On 10/1/2013 10:57 PM, nestork wrote:
No, if an induction motor (which is an electric motor that doesn't have brushes) stops turning for whatever reason, then you effectively have a short circuit through the stator. In that case, current through the stator will quickly exceed the amperage the circuit is fused down to, and you'll simply blow the fuse or trip the breaker that motor is on. As long as it's on a circuit that's fused down to 15 amps, the motor will just blow the fuse and then you no longer have power available to anything on that circuit, including the motor. Take a look at the electrical schematic for an induction electric motor: http://tinyurl.com/qarvcqk This one is a capacitor start motor, but a split phase motor's schamatic would be exactly the same, except that it wouldn't have a capacitor. You have a Main winding and a start winding. The start winding is taken out of the circuit as the motor comes up to speed. If that were a DC circuit, you'd have a dead short through the main winding. The only reason the current through the stator in a real AC electric motor doesn't become excessive is that the main winding sets up an electric field through which the rotor windings spin. That action creates a current in the rotor windings, and the current in the rotor windings creates a magnetic field that opposes the current through the stator windings. This is why electric motor only draw a lot of current when they're starting. Once they're up to speed, the running current is actually quite low, making them highly efficient mechanically. But, if you were to grab onto the rotor and prevent it from turning, you wouldn't have the electrical current generated in the rotor windings and there'd be no opposition to the current flow through the main winding, and the result would be that the current through the main winding would act like a dead short and quickly exceed the amperage of the fuse or circuit breaker that motor is on, shutting down electrical power to the circuit. The motor would only go up in flames if it wasn't fused down to a lower amperage. If it were the convection fan motor in a convection oven that was on a 220 volt 50 amp circuit, then there could be 50 amps going through the stator, in which case it would probably get so hot the flammable parts inside it would probably catch fire. I've never had a convection oven, but I expect the motor of the convection fan has it's own fuse or fusible link so that if current through that stator got excessive, the fuse or fusible link would burn out. Otherwise, it'd be kinda dangerous and a potential fire hazard. I remember from some where, refrigerator compressors have a LRA, or Locked Rotor Amps rating. I think some motors do, also. .. Christopher A. Young Learn about Jesus www.lds.org .. |
What happens when an electrical motor dies?
On Tue, 1 Oct 2013 19:06:20 -0700, "bob" wrote:
If I set up an exhaust fan in the crawlspace that runs non stop, eventually the motor would wear out and fail. Would it go up in flame? Or are all motors used in the usa required to shutdown gracefully? Alot of fans/motors are used in commercial applications. I can't imagine them going up in flames at the end of their lives. Motors I've had fail; generally given early sings / sounds before the seize up and fail. Never had one catch fire. Could you use a timer on the fan? Unless you need 365/24/7. |
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What is locked rotor current According to the above web page, the Locked Rotor Amperage is the current draw during the instant the motor is first turned on and the rotor is effectively still stationary. It's essentially what you're thinking from it's name; the current that would flow through the stator if the rotor weren't turning. That web page says the current through the motor when it's starting is anywhere from 3 to 8 times the current it draws when it's running under full load at normal speed. So, if you have an electric motor that draws 5 amps, it can draw anywhere from 15 to 40 amps when it's first starting. I guess that's why appliances that draw a lot of amperage, like air conditioners and air compressors will often require "Slo Blo" fuses that allow for that high initial tarting current without blowing. |
What happens when an electrical motor dies?
On 10/1/13 9:06 PM, bob wrote:
If I set up an exhaust fan in the crawlspace that runs non stop, eventually the motor would wear out and fail. Would it go up in flame? Or are all motors used in the usa required to shutdown gracefully? Alot of fans/motors are used in commercial applications. I can't imagine them going up in flames at the end of their lives. The motors I'm around are three phase, 480 volt. I've seen wiring going to them burn but not the actual motor. You might want to put the wiring in conduit. The motors sometimes get awfully hot when they fail. More knowledgeable people here might be able to recommend some sort of motor starter as an additional safeguard. |
What happens when an electrical motor dies?
They go to motor heaven.
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What happens when an electrical motor dies?
On 10/3/2013 6:29 AM, Meanie wrote:
They go to motor heaven. I've been wondering if I should float that answer. What if the motor is religious? Do Jewish motors go different than Hindu or Buddhist motors? Would a Jehovas Witness motor door to door, looking for Heaven? -- .. Christopher A. Young Learn about Jesus www.lds.org .. |
What happens when an electrical motor dies?
On Thu, 03 Oct 2013 07:56:11 -0400, Stormin Mormon
wrote: Heaven? Jesus, Jose' and Maria! The Mormon has a new computer? And if that isn't fancy enough, his sig file delimiter worked as it should. Say it is for real and not nym-shiftin'. I predicted the day it would come about. I sure did. I said it right here before g. There is a Jesus. |
What happens when an electrical motor dies?
On 10/3/2013 3:29 PM, Oren wrote:
On Thu, 03 Oct 2013 07:56:11 -0400, Stormin Mormon wrote: Heaven? Jesus, Jose' and Maria! The Mormon has a new computer? And if that isn't fancy enough, his sig file delimiter worked as it should. Say it is for real and not nym-shiftin'. I predicted the day it would come about. I sure did. I said it right here before g. There is a Jesus. Now, read the Book of Mormon twice, pray to know if it's true, and call the LDS missionaries. .. Christopher A. Young Learn about Jesus www.lds.org .. |
What happens when an electrical motor dies?
On Thu, 03 Oct 2013 18:19:24 -0400, Stormin Mormon
wrote: Now, read the Book of Mormon twice, pray to know if it's true, and call the LDS missionaries. Quit yer preachin'. |
What happens when an electrical motor dies?
On 10/4/2013 1:20 PM, Oren wrote:
On Thu, 03 Oct 2013 18:19:24 -0400, Stormin Mormon wrote: Now, read the Book of Mormon twice, pray to know if it's true, and call the LDS missionaries. Quit yer preachin'. I'm trying to establish that it's really me. Did you at least call the LDS missionaries to pray with you? .. Christopher A. Young Learn about Jesus www.lds.org .. |
What happens when an electrical motor dies?
On Tue, 1 Oct 2013 19:06:20 -0700, "bob" wrote:
It goes to electric motor heaven. |
What happens when an electrical motor dies?
On Fri, 04 Oct 2013 14:52:24 -0400, Stormin Mormon
wrote: On 10/4/2013 1:20 PM, Oren wrote: On Thu, 03 Oct 2013 18:19:24 -0400, Stormin Mormon wrote: Now, read the Book of Mormon twice, pray to know if it's true, and call the LDS missionaries. Quit yer preachin'. I'm trying to establish that it's really me. So tell us you have a new computer. Did you at least call the LDS missionaries to pray with you? Why would I do that? I can pray all by my lonesome. |
What happens when an electrical motor dies?
On Fri, 04 Oct 2013 13:01:20 -0700, Oren wrote:
On Fri, 04 Oct 2013 14:52:24 -0400, Stormin Mormon wrote: On 10/4/2013 1:20 PM, Oren wrote: On Thu, 03 Oct 2013 18:19:24 -0400, Stormin Mormon wrote: Now, read the Book of Mormon twice, pray to know if it's true, and call the LDS missionaries. Quit yer preachin'. I'm trying to establish that it's really me. So tell us you have a new computer. Did you at least call the LDS missionaries to pray with you? Why would I do that? I can pray all by my lonesome. ....and give all your money to yourself? |
What happens when an electrical motor dies?
On Tue, 1 Oct 2013 19:06:20 -0700, "bob"
wrote: If I set up an exhaust fan in the crawlspace that runs non stop, eventually the motor would wear out and fail. Would it go up in flame? Or are all motors used in the usa required to shutdown gracefully? Alot of fans/motors are used in commercial applications. I can't imagine them going up in flames at the end of their lives. The motor in a swamp-cooler of mine quietly stopped in the middle of the night a few years back. I woke up and happened to notice that it wasn't running, and went to investigate. Thick, dark smoke was roiling from the swamp-cooler. I immediately unplugged it and went back out to take the shrouds off. I got the hose and started squirting the motor down, but it took about 15 minutes before it stopped spitting and steaming. This cooler was on a 1950s 15a circuit shared with other outlets and lighting. The breaker didn't pop. I don't leave swamp-coolers on overnite anymore! -- croy |
What happens when an electrical motor dies?
On Sat, 05 Oct 2013 12:39:49 -0700, croy
wrote: Alot of fans/motors are used in commercial applications. I can't imagine them going up in flames at the end of their lives. The motor in a swamp-cooler of mine quietly stopped in the middle of the night a few years back. I woke up and happened to notice that it wasn't running, and went to investigate. Thick, dark smoke was roiling from the swamp-cooler. I immediately unplugged it and went back out to take the shrouds off. I got the hose and started squirting the motor down, but it took about 15 minutes before it stopped spitting and steaming. This cooler was on a 1950s 15a circuit shared with other outlets and lighting. The breaker didn't pop. I don't leave swamp-coolers on overnite anymore! So you had no fire on the motor. By "unplugged", you mean a portable unit? Long term, house swamp coolers are normally hard-wired in to the house wiring. |
What happens when an electrical motor dies?
On Sat, 05 Oct 2013 15:22:17 -0700, Oren wrote:
On Sat, 05 Oct 2013 12:39:49 -0700, croy wrote: Alot of fans/motors are used in commercial applications. I can't imagine them going up in flames at the end of their lives. The motor in a swamp-cooler of mine quietly stopped in the middle of the night a few years back. I woke up and happened to notice that it wasn't running, and went to investigate. Thick, dark smoke was roiling from the swamp-cooler. I immediately unplugged it and went back out to take the shrouds off. I got the hose and started squirting the motor down, but it took about 15 minutes before it stopped spitting and steaming. This cooler was on a 1950s 15a circuit shared with other outlets and lighting. The breaker didn't pop. I don't leave swamp-coolers on overnite anymore! So you had no fire on the motor. By "unplugged", you mean a portable unit? Long term, house swamp coolers are normally hard-wired in to the house wiring. can't speak for the rest of teh country but here in AZ, at least in the "old days" when most people had swamp coolers, they were not hardwired. There was a hardwired receptacle placed on the wall where the cooler was hung and the cooler was plugged into that. Even for two speed coolers they had a multiple prong outlet that the cooler plugged into. It was not unusual to buy a new cooler every ten years due to them corroding away. You bought a new one, plopped it into the metal frame that hung on the side of the house, screwed the duct back on, plugged it in and away you went. |
What happens when an electrical motor dies?
On Sat, 05 Oct 2013 20:32:34 -0700, Ashton Crusher
wrote: On Sat, 05 Oct 2013 15:22:17 -0700, Oren wrote: On Sat, 05 Oct 2013 12:39:49 -0700, croy wrote: Alot of fans/motors are used in commercial applications. I can't imagine them going up in flames at the end of their lives. The motor in a swamp-cooler of mine quietly stopped in the middle of the night a few years back. I woke up and happened to notice that it wasn't running, and went to investigate. Thick, dark smoke was roiling from the swamp-cooler. I immediately unplugged it and went back out to take the shrouds off. I got the hose and started squirting the motor down, but it took about 15 minutes before it stopped spitting and steaming. This cooler was on a 1950s 15a circuit shared with other outlets and lighting. The breaker didn't pop. I don't leave swamp-coolers on overnite anymore! So you had no fire on the motor. By "unplugged", you mean a portable unit? Long term, house swamp coolers are normally hard-wired in to the house wiring. can't speak for the rest of teh country but here in AZ, at least in the "old days" when most people had swamp coolers, they were not hardwired. There was a hardwired receptacle placed on the wall where the cooler was hung and the cooler was plugged into that. Even for two speed coolers they had a multiple prong outlet that the cooler plugged into. It was not unusual to buy a new cooler every ten years due to them corroding away. You bought a new one, plopped it into the metal frame that hung on the side of the house, screwed the duct back on, plugged it in and away you went. Ten years? Just how hard do you think it is to rewire a box? |
What happens when an electrical motor dies?
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What happens when an electrical motor dies?
On 10/6/2013 10:25 AM, Oren wrote:
.... Seems silly to not hardwire a roof mounted swamp cooler (IMO) Virtually none were anything but window units back then other than commercial... I've never seen anything but the wall outlet for one in a home; the load is simply the fan and a tiny little pump, not a compressor so there's no need for anything more than 15A service. -- |
What happens when an electrical motor dies?
On Sun, 06 Oct 2013 11:03:19 -0500, dpb wrote:
On 10/6/2013 10:25 AM, Oren wrote: ... Seems silly to not hardwire a roof mounted swamp cooler (IMO) Virtually none were anything but window units back then other than commercial... I've never seen anything but the wall outlet for one in a home; the load is simply the fan and a tiny little pump, not a compressor so there's no need for anything more than 15A service. I guess it's awkward to permanently wire something into a window unit. Just routing the cables would be a pain. Even our thru-the-wall ACs (one 240V, one 120V) were plugged in. OTOH, I'd expect a roof-mounted unit to be permanently wired. |
What happens when an electrical motor dies?
On Sat, 05 Oct 2013 15:22:17 -0700, Oren
wrote: So you had no fire on the motor. By "unplugged", you mean a portable unit? Long term, house swamp coolers are normally hard-wired in to the house wiring. It was a "built-in" unit, added sometime after the house was built, by the previous owners. It was stuck in a hole they cut in the side of the house (cutting right thru a diagonal brace, no less). It had a typical appliance-type power cord that plugged into the wall outlet. I had replaced the service entrance panel and installed all new breakers, but the wiring remained original. I opted to replace it with a roof-mounted unit, hard-wired with its own 20a circuit, with all new wire. Now we'll see what it does to try to get me. -- croy |
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