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How is a motor rewound to operate on a different voltage?
For example, A motor voltage 3x230V to voltage 3x400V. Section of wires original / V3(1,73) Number of windings original x V3 (1,73) Connections of coils have to stay the same, as well as external connections. Most motors do have different voltage regarding the external connection. Most motors < 5,5kW = 3x230V/400V 5,5kW and higher : 3x400V/690V The difference between the voltage is in this case made by external connection (Delta/star) Delta : L1 = U1-W2, L2 = V1-U2, L3 = W1-V2 Star : L1 = U1, L2 = V1, L3 = W1 and connection between U2-V2-W2
Can you use HT cable in place of Lt cable?
For LT cable 1. Use : Up to 690V 2. Insulation : PVC 3. Core(Neutral) : Yes 4. Insulation Grading : 1100 V For HT cable 1. Use : Above 690 2. Insulation : XLPE 3. Core(Neutral) : No 4. Insulation Grading : Above 3.3kV, 11KV..etc ( Please note that now 690 V using in VFD application with LV cable and 440 V for DOT motor starter) from Kunal Singh Dabi the_dabi@rediffmaill.com
Why is 50 hz 690V preferred over 440V in electric systems . Is there any benefits for 690V over 440V or vice versa . please answer?
At 690V the currents are smaller resulting in smaller rated equipment (smaller cables, transformers, switchboards, equipment ..etc) at 690V the running current is reduced by40% compared to the 400V system and the energy losses due to hear are much smaller compared to the 400V system. many motors are on the border line for a service voltage of 400V but they can easily be accommodated at a service voltage of 690/400V. refer to IEC 60038 edition 6.2 2002-07.
How do you connect 400 motor to run with 690?
You don't, unless the motor doesn't have to last very long. that's a 173% of the motor voltage rating (690volts / 400 volts), at best you can get away with ~110%. The motor will become overexcited, overheat, overspeed, and fail. You must step the voltage down to a reasonable level for the motor. You could use power electronics for this, or a transformer. If your source is a four wire, 690v system (the line to line voltage is 690v), then you should be able to run the motor wired line to neutral. You should verify this won't overload anything, and won't cause excessive unbalance on your three phase.
How is a motor rewound to operate on a different voltage?
For example, A motor voltage 3x230V to voltage 3x400V. Section of wires original / V3(1,73) Number of windings original x V3 (1,73) Connections of coils have to stay the same, as well as external connections. Most motors do have different voltage regarding the external connection. Most motors < 5,5kW = 3x230V/400V 5,5kW and higher : 3x400V/690V The difference between the voltage is in this case made by external connection (Delta/star) Delta : L1 = U1-W2, L2 = V1-U2, L3 = W1-V2 Star : L1 = U1, L2 = V1, L3 = W1 and connection between U2-V2-W2
Can you use HT cable in place of Lt cable?
For LT cable 1. Use : Up to 690V 2. Insulation : PVC 3. Core(Neutral) : Yes 4. Insulation Grading : 1100 V For HT cable 1. Use : Above 690 2. Insulation : XLPE 3. Core(Neutral) : No 4. Insulation Grading : Above 3.3kV, 11KV..etc ( Please note that now 690 V using in VFD application with LV cable and 440 V for DOT motor starter) from Kunal Singh Dabi the_dabi@rediffmaill.com
