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Electrical Motors - for use in India 3
- Thread starter marshda1
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Skogsgurra
Electrical
I had a problem in India once. Or rather a customer of mine. It seems that not only the food is hot. Many factories in southern India are also hot.
This customer had huge problems with bearing currents in an application that didn't present any problems at all in other places. It turned out that voltage across the bearings was zero.
Zero is usually a good thing. But not if the reason for zero volts is hot grease. So hot that the oil film was too thin to insulate. Continuous conduction all the time led to EDM and premature bearing failures.
You may need High Temperature Grease and, perhaps, common-mode filters. Check with end user what ambient temperature the motors are supposed to work in.
Gunnar Englund
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Half full - Half empty? I don't mind. It's what in it that counts.
This customer had huge problems with bearing currents in an application that didn't present any problems at all in other places. It turned out that voltage across the bearings was zero.
Zero is usually a good thing. But not if the reason for zero volts is hot grease. So hot that the oil film was too thin to insulate. Continuous conduction all the time led to EDM and premature bearing failures.
You may need High Temperature Grease and, perhaps, common-mode filters. Check with end user what ambient temperature the motors are supposed to work in.
Gunnar Englund
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
- Thread starter
- #4
Thanks for the information.
I found the following on an internet search, don't know if could be related to your comments about high temperature operation.
India uses 240 V and 50 Hz
US 240 V and 60 Hz
Using a 60Hz motor in 50Hz duty.
w) It will turn 20% slower.
x) Cooling will drop dramatically.
y) The load's horsepower requirements will drop, possibly dramatically.
z) V/f will increase possibly causing a large increase in current draw.
Make sure the load will still do what is required of it when running slower.
The cooling will reduce dramatically. Is it enough to matter? This depends on how the load has decreased. If the hp requirement dropped because the load has decreased the current will drop and less heat will be released internally. You would want to take temperature measurements until the motor reaches a steady state temperature running in its new frequency application.
The most serious issue is the V/f issue. The V/f will increase. Likely enough to cause a large increase in the motor's current. This coupled with the reduced cooling may cause rapid overheating.
I found the following on an internet search, don't know if could be related to your comments about high temperature operation.
India uses 240 V and 50 Hz
US 240 V and 60 Hz
Using a 60Hz motor in 50Hz duty.
w) It will turn 20% slower.
x) Cooling will drop dramatically.
y) The load's horsepower requirements will drop, possibly dramatically.
z) V/f will increase possibly causing a large increase in current draw.
Make sure the load will still do what is required of it when running slower.
The cooling will reduce dramatically. Is it enough to matter? This depends on how the load has decreased. If the hp requirement dropped because the load has decreased the current will drop and less heat will be released internally. You would want to take temperature measurements until the motor reaches a steady state temperature running in its new frequency application.
The most serious issue is the V/f issue. The V/f will increase. Likely enough to cause a large increase in the motor's current. This coupled with the reduced cooling may cause rapid overheating.
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- #5
Hence:
Step 1) Look up the voltage used in India.
Step 2) Match it.
If you send a single phase (because you mention 240V) motor to India that was designed for use in the US, it is doomed to fail.
Buy a 230V 50hz motor for your machines going to any country outside of North America. Or use 3 phase, that is easier to deal with (long story, but let us know if you want to consider it). But either way, you will need to evaluate what effects your machine will have from the motor running 20% slower. My crystal ball cannot see what your machine is, sorry.
"Will work for salami"
Step 1) Look up the voltage used in India.
Step 2) Match it.
If you send a single phase (because you mention 240V) motor to India that was designed for use in the US, it is doomed to fail.
Buy a 230V 50hz motor for your machines going to any country outside of North America. Or use 3 phase, that is easier to deal with (long story, but let us know if you want to consider it). But either way, you will need to evaluate what effects your machine will have from the motor running 20% slower. My crystal ball cannot see what your machine is, sorry.
"Will work for salami"
You should not only match the motor to the power supply but you should match the equipment requirements to the lower motor speed. Specifically, it may not be enough to simply install a 50hz motor on the existing equipment that was designed for 60hz speeds.
For a hoist or conveyor, when changing changing the speed from 60hz to 50hz, the device will run at 83% of the original speed. The slower speed may or may not be be a problem depending on the customer requirements.
However, for a centrifugal compressor, pump, or fan, the flow will be reduced proportional to the reduction in speed so that the new flow will be 83% of the original flow. More importantly, the output pressure (or pump head) will be reduced proportion to the square of the reduction in speed so that the new pressure will be 69% of the original pressure. Depending on the application that the compressor, pump, or fan is used for, the reduction in flow and pressure may render the equipment inoperable.
For a hoist or conveyor, when changing changing the speed from 60hz to 50hz, the device will run at 83% of the original speed. The slower speed may or may not be be a problem depending on the customer requirements.
However, for a centrifugal compressor, pump, or fan, the flow will be reduced proportional to the reduction in speed so that the new flow will be 83% of the original flow. More importantly, the output pressure (or pump head) will be reduced proportion to the square of the reduction in speed so that the new pressure will be 69% of the original pressure. Depending on the application that the compressor, pump, or fan is used for, the reduction in flow and pressure may render the equipment inoperable.
1 Phase voltage in India is 230V 50Hz & 3 Phase varies from 380V to 440V, 50Hz depending upon the application & field conditions.
In case of industrial application a 415V,50Hz (380V,60Hz) motor will solve the issue. If your equipments motors are for agricultural/similar field application then really you are gonna have a tough time ahead because, energy distribution for agricultural sector is not proper in India which lead to huge voltage fluctuations.
In case of industrial application a 415V,50Hz (380V,60Hz) motor will solve the issue. If your equipments motors are for agricultural/similar field application then really you are gonna have a tough time ahead because, energy distribution for agricultural sector is not proper in India which lead to huge voltage fluctuations.
Please read the 60Hz voltage as 460V, 60Hz
In case of industrial application a 400-415V,50Hz (460V,60Hz) motor will solve the issue. If your equipments motors are for agricultural/similar field application then really you are gonna have a tough time ahead because, energy distribution for agricultural sector is not proper in India which lead to huge voltage fluctuations.
In case of industrial application a 400-415V,50Hz (460V,60Hz) motor will solve the issue. If your equipments motors are for agricultural/similar field application then really you are gonna have a tough time ahead because, energy distribution for agricultural sector is not proper in India which lead to huge voltage fluctuations.
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