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#1
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running 120V muffin fan on 240V
Deep down I already know the answer to this is NO, but on the off
chance someone knows something I don't... I have an old Lincoln "buzz box" welder with a dead cooling fan. Parts to fix will run $76 and change. I also have a Radio Shack 120V muffin fan #273-241 that's the right size. $25 is much better than $75. The original fan is 220V. I can wire up the new fan as 120V, but what would really be great is if I could wire it up as 240V. That'd move a whole lot more air. Will the fan be able to deal with the higher voltage? |
#2
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running 120V muffin fan on 240V
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#3
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running 120V muffin fan on 240V
Although it may be possible to run the 120 fan motor on 220 without damaging
it, you would be wrong to think that you would get a lot more airflow because the speed of an induction motor is primarily a function of the frequency of the power source, not the voltage. Typical induction motors run at only slightly less than the synchronous speed - for example 1725 rpm vs 1800 rpm synchronous. You might get this up to 1760 by running it at 220 but it's not going to double or anything close to double. wrote in message oups.com... Deep down I already know the answer to this is NO, but on the off chance someone knows something I don't... I have an old Lincoln "buzz box" welder with a dead cooling fan. Parts to fix will run $76 and change. I also have a Radio Shack 120V muffin fan #273-241 that's the right size. $25 is much better than $75. The original fan is 220V. I can wire up the new fan as 120V, but what would really be great is if I could wire it up as 240V. That'd move a whole lot more air. Will the fan be able to deal with the higher voltage? |
#4
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running 120V muffin fan on 240V
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#6
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running 120V muffin fan on 240V
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#7
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running 120V muffin fan on 240V
I think if you do the analysis that you will find that adding the capacitor
in series will actually result in higher current in the motor than just connecting it to the 220 directly. The reactance of the capacitor will be 180 out of phase with the reactance of the motor windings and so will exactly cancel it out and the current will only be limited by the resistance of the motor windings -- the worst case possible as far as overheating the motor goes. Inserting a series resistance or another fan motor in series would be the safest solution although I still don't think the motor would be damaged by just connecting it directly. "Ross Herbert" wrote in message ... On 30 Jan 2007 11:49:20 -0800, wrote: Deep down I already know the answer to this is NO, but on the off chance someone knows something I don't... I have an old Lincoln "buzz box" welder with a dead cooling fan. Parts to fix will run $76 and change. I also have a Radio Shack 120V muffin fan #273-241 that's the right size. $25 is much better than $75. The original fan is 220V. I can wire up the new fan as 120V, but what would really be great is if I could wire it up as 240V. That'd move a whole lot more air. Will the fan be able to deal with the higher voltage? Radio Shack 273-241 is rated at 120V, 22W (approx 180mA) You could wire a 4uF (or close) MKP motor start cap in series with the fan. At 60 Hz this should give about 660 ohms series reactance which should drop 120V at 180mA if my arithmetic is correct. |
#8
Posted to alt.electronics
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running 120V muffin fan on 240V
----------------------------
"Ross Herbert" wrote in message ... On 30 Jan 2007 11:49:20 -0800, wrote: Deep down I already know the answer to this is NO, but on the off chance someone knows something I don't... I have an old Lincoln "buzz box" welder with a dead cooling fan. Parts to fix will run $76 and change. I also have a Radio Shack 120V muffin fan #273-241 that's the right size. $25 is much better than $75. The original fan is 220V. I can wire up the new fan as 120V, but what would really be great is if I could wire it up as 240V. That'd move a whole lot more air. Will the fan be able to deal with the higher voltage? Radio Shack 273-241 is rated at 120V, 22W (approx 180mA) You could wire a 4uF (or close) MKP motor start cap in series with the fan. At 60 Hz this should give about 660 ohms series reactance which should drop 120V at 180mA if my arithmetic is correct. ------------- Whether the capacitor idea would work or not depends on the type of motor. If it is induction, you could end up with well over rated voltage on the fan due to resonance. definitely not a good idea with inductive devices. Also the power being 22 watts doesn't necessarily mean that the current is 0.18A -it could be more because of power factor. The motor could be shaded pole induction or possibly brushless DC. I expect that the original was shaded pole. What the radio shack one is is unknown- and its ruggedness in the particular application is questionable. Unfortunately the best solution is simply to bite the bullet and replace the fan with a 240V model. try http://www.surplussales.com/Fans-Blo...ansBlow-3.html Don Kelly remove the X to answer |
#9
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running 120V muffin fan on 240V
On Wed, 31 Jan 2007 18:54:40 GMT, "Don Kelly" wrote:
---------------------------- "Ross Herbert" wrote in message .. . On 30 Jan 2007 11:49:20 -0800, wrote: Deep down I already know the answer to this is NO, but on the off chance someone knows something I don't... I have an old Lincoln "buzz box" welder with a dead cooling fan. Parts to fix will run $76 and change. I also have a Radio Shack 120V muffin fan #273-241 that's the right size. $25 is much better than $75. The original fan is 220V. I can wire up the new fan as 120V, but what would really be great is if I could wire it up as 240V. That'd move a whole lot more air. Will the fan be able to deal with the higher voltage? Radio Shack 273-241 is rated at 120V, 22W (approx 180mA) You could wire a 4uF (or close) MKP motor start cap in series with the fan. At 60 Hz this should give about 660 ohms series reactance which should drop 120V at 180mA if my arithmetic is correct. ------------- Whether the capacitor idea would work or not depends on the type of motor. If it is induction, you could end up with well over rated voltage on the fan due to resonance. definitely not a good idea with inductive devices. Also the power being 22 watts doesn't necessarily mean that the current is 0.18A -it could be more because of power factor. The motor could be shaded pole induction or possibly brushless DC. I expect that the original was shaded pole. What the radio shack one is is unknown- and its ruggedness in the particular application is questionable. Unfortunately the best solution is simply to bite the bullet and replace the fan with a 240V model. try http://www.surplussales.com/Fans-Blo...ansBlow-3.html Don Kelly remove the X to answer I have used this method with low powered ac fans usually as a cheap way of running them at less than maximum speed and I have not noticed any exccessive heating of the motor. |
#10
Posted to alt.electronics
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running 120V muffin fan on 240V
Not really the same situation though is it Ross.
I guess mkirsch1 has taken the option of hooking his 120volt fan up to the 120volts available and left us all here spinning our wheels. "Ross Herbert" wrote in message ... On Wed, 31 Jan 2007 18:54:40 GMT, "Don Kelly" wrote: ---------------------------- "Ross Herbert" wrote in message . .. On 30 Jan 2007 11:49:20 -0800, wrote: Deep down I already know the answer to this is NO, but on the off chance someone knows something I don't... I have an old Lincoln "buzz box" welder with a dead cooling fan. Parts to fix will run $76 and change. I also have a Radio Shack 120V muffin fan #273-241 that's the right size. $25 is much better than $75. The original fan is 220V. I can wire up the new fan as 120V, but what would really be great is if I could wire it up as 240V. That'd move a whole lot more air. Will the fan be able to deal with the higher voltage? Radio Shack 273-241 is rated at 120V, 22W (approx 180mA) You could wire a 4uF (or close) MKP motor start cap in series with the fan. At 60 Hz this should give about 660 ohms series reactance which should drop 120V at 180mA if my arithmetic is correct. ------------- Whether the capacitor idea would work or not depends on the type of motor. If it is induction, you could end up with well over rated voltage on the fan due to resonance. definitely not a good idea with inductive devices. Also the power being 22 watts doesn't necessarily mean that the current is 0.18A -it could be more because of power factor. The motor could be shaded pole induction or possibly brushless DC. I expect that the original was shaded pole. What the radio shack one is is unknown- and its ruggedness in the particular application is questionable. Unfortunately the best solution is simply to bite the bullet and replace the fan with a 240V model. try http://www.surplussales.com/Fans-Blo...ansBlow-3.html Don Kelly remove the X to answer I have used this method with low powered ac fans usually as a cheap way of running them at less than maximum speed and I have not noticed any exccessive heating of the motor. |
#12
Posted to alt.electronics
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running 120V muffin fan on 240V
"Ross Herbert" wrote in message
... On Wed, 31 Jan 2007 18:54:40 GMT, "Don Kelly" wrote: ---------------------------- "Ross Herbert" wrote in message . .. On 30 Jan 2007 11:49:20 -0800, wrote: Deep down I already know the answer to this is NO, but on the off chance someone knows something I don't... I have an old Lincoln "buzz box" welder with a dead cooling fan. Parts to fix will run $76 and change. I also have a Radio Shack 120V muffin fan #273-241 that's the right size. $25 is much better than $75. The original fan is 220V. I can wire up the new fan as 120V, but what would really be great is if I could wire it up as 240V. That'd move a whole lot more air. Will the fan be able to deal with the higher voltage? Radio Shack 273-241 is rated at 120V, 22W (approx 180mA) You could wire a 4uF (or close) MKP motor start cap in series with the fan. At 60 Hz this should give about 660 ohms series reactance which should drop 120V at 180mA if my arithmetic is correct. ------------- Whether the capacitor idea would work or not depends on the type of motor. If it is induction, you could end up with well over rated voltage on the fan due to resonance. definitely not a good idea with inductive devices. Also the power being 22 watts doesn't necessarily mean that the current is 0.18A -it could be more because of power factor. The motor could be shaded pole induction or possibly brushless DC. I expect that the original was shaded pole. What the radio shack one is is unknown- and its ruggedness in the particular application is questionable. Unfortunately the best solution is simply to bite the bullet and replace the fan with a 240V model. try http://www.surplussales.com/Fans-Blo...ansBlow-3.html Don Kelly remove the X to answer I have used this method with low powered ac fans usually as a cheap way of running them at less than maximum speed and I have not noticed any exccessive heating of the motor. --------------------------- Saved by a high R/X ratio when running. Did you take any voltage measurements across capacitor and motor? -- Don Kelly remove the X to answer ---------------------------- |
#13
Posted to alt.electronics
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running 120V muffin fan on 240V
On Fri, 02 Feb 2007 03:06:02 GMT, "Don Kelly" wrote:
"Ross Herbert" wrote in message .. . On Wed, 31 Jan 2007 18:54:40 GMT, "Don Kelly" wrote: ---------------------------- "Ross Herbert" wrote in message ... On 30 Jan 2007 11:49:20 -0800, wrote: Deep down I already know the answer to this is NO, but on the off chance someone knows something I don't... I have an old Lincoln "buzz box" welder with a dead cooling fan. Parts to fix will run $76 and change. I also have a Radio Shack 120V muffin fan #273-241 that's the right size. $25 is much better than $75. The original fan is 220V. I can wire up the new fan as 120V, but what would really be great is if I could wire it up as 240V. That'd move a whole lot more air. Will the fan be able to deal with the higher voltage? Radio Shack 273-241 is rated at 120V, 22W (approx 180mA) You could wire a 4uF (or close) MKP motor start cap in series with the fan. At 60 Hz this should give about 660 ohms series reactance which should drop 120V at 180mA if my arithmetic is correct. ------------- Whether the capacitor idea would work or not depends on the type of motor. If it is induction, you could end up with well over rated voltage on the fan due to resonance. definitely not a good idea with inductive devices. Also the power being 22 watts doesn't necessarily mean that the current is 0.18A -it could be more because of power factor. The motor could be shaded pole induction or possibly brushless DC. I expect that the original was shaded pole. What the radio shack one is is unknown- and its ruggedness in the particular application is questionable. Unfortunately the best solution is simply to bite the bullet and replace the fan with a 240V model. try http://www.surplussales.com/Fans-Blo...ansBlow-3.html Don Kelly remove the X to answer I have used this method with low powered ac fans usually as a cheap way of running them at less than maximum speed and I have not noticed any exccessive heating of the motor. --------------------------- Saved by a high R/X ratio when running. Did you take any voltage measurements across capacitor and motor? Nope! Simple empirical method of testing - finger on motor frame. If I took out my scope and took measurements the results would surely have told me that the method was not advisable. Since it worked without any problems I preferred to take this as a sign of its effectiveness for the application. |
#14
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running 120V muffin fan on 240V
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