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#1
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Microwave turntable
I have a Sharp MW. The turntable sometimes rotates
clockwise,othertimes it rotates counter-clockwise.If someone knows the reason why,I would appreciate an answer.No one so far has been able to explain this.Just some FOOD for thought! Thanx |
#2
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Microwave turntable
Lee burch wrote in message ... I have a Sharp MW. The turntable sometimes rotates clockwise,othertimes it rotates counter-clockwise.If someone knows the reason why,I would appreciate an answer.No one so far has been able to explain this.Just some FOOD for thought! Thanx Most models reverse every time the MW is started. In some cases, the food should be stirred part way though the cycle. After you do that, the turntable reverses, allegedly to help cook more evenly. |
#3
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Microwave turntable
Lee burch wrote in message
... I have a Sharp MW. The turntable sometimes rotates clockwise,othertimes it rotates counter-clockwise.If someone knows the reason why,I would appreciate an answer.No one so far has been able to explain this. What did the manufacturer say when you messaged the Sharp web site ? -- Don Phillipson Carlsbad Springs (Ottawa, Canada) |
#4
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Microwave turntable
Well, if it always turns in one
direction the food will tangle, so you must untangle ..... just kidding. Many gear-head motors that run on 110 AC, have "shading rings" to set up the magnetic field so they always rotate in the same direction. These are 1 turn chunks of copper that will go through and/or around the steel laminations. I have noticed in the last few years, many small motors like that, don't have shading rings and will start in a random direction. I guess if it doesn't make any difference, like in a microwave turntable, it makes the motor $0.00001 cheaper. BTW, my microwave does the same thing. Lee burch wrote: I have a Sharp MW. The turntable sometimes rotates clockwise,othertimes it rotates counter-clockwise.If someone knows the reason why,I would appreciate an answer.No one so far has been able to explain this.Just some FOOD for thought! Thanx |
#5
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Microwave turntable
Art Todesco wrote:
Well, if it always turns in one direction the food will tangle, so you must untangle ..... just kidding. Many gear-head motors that run on 110 AC, have "shading rings" to set up the magnetic field so they always rotate in the same direction. These are 1 turn chunks of copper that will go through and/or around the steel laminations. I have noticed in the last few years, many small motors like that, don't have shading rings and will start in a random direction. What kind of motors do you think those are? AFAIK, without shading rings a simple induction motor will not self start. But, there are all sorts of small motor designs around now I never encountered when I was a kid, just think about what's in a modern automobile. Perhaps they're using DC motors, two phase AC motors, or some kind of stepper motor for those microwave turntables now, driven by a few components on the appliance's circuit board. Based on what Edwin said, I doubt that the starting direction is really "random". Jeff I guess if it doesn't make any difference, like in a microwave turntable, it makes the motor $0.00001 cheaper. BTW, my microwave does the same thing. I know my 4 year old GE microwave's turntable always rotates in the same direction as my grandma's Victrola's, but it might be interesting for the OP to run some tests or even, G-d forbid, RTFM and let us know if it's really random. Jeff -- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) The speed of light is 1.98*10^14 fathoms per fortnight. |
#6
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Microwave turntable
Jeff Wisnia wrote:
Art Todesco wrote: Well, if it always turns in one direction the food will tangle, so you must untangle ..... just kidding. Many gear-head motors that run on 110 AC, have "shading rings" to set up the magnetic field so they always rotate in the same direction. These are 1 turn chunks of copper that will go through and/or around the steel laminations. I have noticed in the last few years, many small motors like that, don't have shading rings and will start in a random direction. What kind of motors do you think those are? AFAIK, without shading rings a simple induction motor will not self start. But, there are all sorts of small motor designs around now I never encountered when I was a kid, just think about what's in a modern automobile. Perhaps they're using DC motors, two phase AC motors, or some kind of stepper motor for those microwave turntables now, driven by a few components on the appliance's circuit board. Based on what Edwin said, I doubt that the starting direction is really "random". Jeff I guess if it doesn't make any difference, like in a microwave turntable, it makes the motor $0.00001 cheaper. BTW, my microwave does the same thing. I know my 4 year old GE microwave's turntable always rotates in the same direction as my grandma's Victrola's, but it might be interesting for the OP to run some tests or even, G-d forbid, RTFM and let us know if it's really random. Jeff You're right. I even saw a motor with a mechanical direction unit. If it went the "wrong" way, it bounced off a ratchet device and went the other way. But I thought a small motor with a rotor would self start. It's just the synchronous ones that wouldn't start by themselves unless something it added. I know old (very old) clocks had to be "spun" to get them going. They too, would go either way. But, as you stated, it's probablythe way the whole thing was designed. |
#7
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Microwave turntable
061217 0918 - Lee burch posted:
I have a Sharp MW. The turntable sometimes rotates clockwise,othertimes it rotates counter-clockwise.If someone knows the reason why,I would appreciate an answer.No one so far has been able to explain this.Just some FOOD for thought! Thanx That's the nature of the type of syncronous motor installed in most turntables. It depends on where in the AC cycle the motor is started as to what direction it will go. If the motor is turned on at the rise of the cycle, the motor will go one way; if on the downturn of the cycle, it will go the opposite. It doesn't really matter, as long as the turntable turns. |
#8
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Microwave turntable
Lee burch wrote:
I have a Sharp MW. The turntable sometimes rotates clockwise,othertimes it rotates counter-clockwise.If someone knows the reason why,I would appreciate an answer.No one so far has been able to explain this.Just some FOOD for thought! Thanx No it isn't food for thought; it is just an ignorant thought. The damn thing is made to operate that way! Read the manual! |
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