cbr shadow
1 kW
Can someone explain what the difference between phase current and rated current is? If I want to run 40amps through my controller, that would be Rated current, right?
Phase currect vs Rated current
- Thread starter cbr shadow
- Start date
Jeremy Harris
100 MW
Phase current is the current that is flowing through the windings of the motor, and "rated current" is the Chinese term for the battery current, the current drawn from the supply.
Battery current is always lower than, or the same as, the phase current. Phase current can be several times higher than battery current under some conditions.
When we refer to current limits here we're normally talking about battery current ("rated current"). The exception to this general rule is the Kelly range of controllers, where, presumably for marketing hype reasons, they tend to refer to current limits as phase current.
The reason phase current can be higher than battery current at times is down to the way the controller works. It's really a switched mode power converter, like that used in power supplies, so can convert a higher voltage at a lower current into a lower voltage at a higher current. When a motor is running slowly, but under a heavy load, it will have a low voltage across the windings, but will need a high current to generate enough torque. The controller allows this, by converting the battery voltage down to a lower voltage at a higher current.
Battery current is always lower than, or the same as, the phase current. Phase current can be several times higher than battery current under some conditions.
When we refer to current limits here we're normally talking about battery current ("rated current"). The exception to this general rule is the Kelly range of controllers, where, presumably for marketing hype reasons, they tend to refer to current limits as phase current.
The reason phase current can be higher than battery current at times is down to the way the controller works. It's really a switched mode power converter, like that used in power supplies, so can convert a higher voltage at a lower current into a lower voltage at a higher current. When a motor is running slowly, but under a heavy load, it will have a low voltage across the windings, but will need a high current to generate enough torque. The controller allows this, by converting the battery voltage down to a lower voltage at a higher current.
cbr shadow
1 kW
I appreciate the detailed explanation - it makes more sense now. Thanks!
footloose
10 kW
Jeremy --
Thank you for concise explanation of phase current.
While I had already found good advice as to multiplier for phase vs line, was perplexed as to why.
Thought I might have to enroll in M.I.T. electrical engineering program for answer until I found this post.
Thank you for concise explanation of phase current.
While I had already found good advice as to multiplier for phase vs line, was perplexed as to why.
Thought I might have to enroll in M.I.T. electrical engineering program for answer until I found this post.
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