Hi recently i did a bearing replacement of a single phase induction motor which was manufactured in 1990s. below specs were printed on its nameplate.

HP : 0.75
Voltage : 230V
Amps : 4A

is 4A the maximum current drawn by motor when it's working ? thank you

 

Hi recently i did a bearing replacement of a single phase induction motor which was manufactured in 1990s. below specs were printed on its nameplate.

HP : 0.75
Voltage : 230V
Amps : 4A

is 4A the maximum current drawn by motor when it's working ? thank you

Yes. Its startup current will be more than that.

 

The startup current may be 10 x the rated current for a short time (few seconds) on an ac induction motor, depending on the starting method..

The running current in unloaded condition (just a spinning shaft for example) for a small motor is usually around 35 to 40% of rated current.

So for a 4A rated motor will be around 1.5amps.

As the motor load is increased, (coupled to a pump, or a fan blowing air for example) the current will rise.
The load on it should not be increased any more, when the current reaches 4 amps.
If the load continues to increase, the current will continue to increase above 4 amps, but the motor is then in an overload condition.
Small motors can typically cope with short term 25% overloads at rated speed with no problems.

 

Larger motors usually have two specs on the nameplate; LRA which is locked rotor amps, and FLA which is full load amps.

 

@Ian0 thank you.
@JohnSan thank you. yes this one has an overload switch too.
@schmitt trigger thank you.