neutral on three phase motors

[m4fiaafg]

please can anyon tell me do three phase motors have or have not got neutral, please if you can for star and delta thanks

 

[Des 56]

please can anyon tell me do three phase motors have or have not got neutral, please if you can for star and delta thanks

If your question is related to the return path
Three phase motors do not require a neutral to operate because the return is via the other phases

Star and delta are just different ways of connecting the coil windings together

 

[m4fiaafg]

please can you talk abit more on it, i was told something about balanced loads or some thing along those lines, cheers

 

[thepurple1]

You dont need a neutral for a 3 phase motor, the rating plate on the motor will tell you how to connect it up. Star or Delta, delta has a triangle symbol and Star has Y symbol . this is just how the motor windings are connected, series or parallel

 

[ian.settle1]

A neutral in connection with 3 phase motor finish at the control panel which is is used for control circuitury.

A neutral maybe at the motor terminal box would be used for a anti condensation heater fitted within the motor.

 

[Des 56]

please can you talk abit more on it, i was told something about balanced loads or some thing along those lines, cheers

Balanced loads are refered to when 3 phase systems supply both 3 and single phase equipment
making the loads of each phase as close to equal as possible
Also for keeping the power factor of the installation as near as possible to perfection
This is the relationship between the current and voltage variation ( sine waves)
Many motors which are inductive loads can make the current lag behind the voltage(not good)
Capacitive loads or capacitors have the reverse effect
So keeping the system equal with regards inductunce and capacatance is better for the efficiancy of the supply that you may have

 

[m4fiaafg]

balanced loads

hello everyone, can some one please tell me why unbalanced loads are more expensiver to run than balanced loads, is this because of powerfactor correction? am i on the right lines. please can you explain in as much detail as possible

cheers

 

[Darkwood]

I smell an essay question or two, if so having others spin out the answers for you will not help you learn, it will only hold you back when you are out on the field doing the work where this understanding is necessary.
If these are just genuine inquisitive questions then ignore this post and keep up the good interest in the subject, it was just the 'as much detail as possible' makes it sound like revision and if you had already studied it you should only need a reminder not a detailed answer.

 

[sparks1234]

I smell an essay question or two, if so having others spin out the answers for you will not help you learn, it will only hold you back when you are out on the field doing the work where this understanding is necessary.
If these are just genuine inquisitive questions then ignore this post and keep up the good interest in the subject, it was just the 'as much detail as possible' makes it sound like revision and if you had already studied it you should only need a reminder not a detailed answer.

A bit harsh, there are probably a few sparks on here unaware of such a problem exists, a brief overview may not go amiss, not really an everyday problem for a lot of sparks

 

[adderzigzag]

Three phase motors rarely have a neutral connection, certainly not on the 'power side' it may be possible a neutral exists if an anticondensation heater is fitted as this usually a 230Vac or 110Vac device. You mention star/delta, these motors have both ends of each winding terminated in the terminal box giving a total of 6 terminations. The terminals can be fitted with shorting link to configure the motor for direct on line operation, either star or delta. if you wish to use a star/delta starter dont assume it can work with any motor. The windings must be capable of at least 440V as when configured in delta as this will be the potential across a winding. This is often not the case with motors these days, best to check rating plate.
Good luck, Nigel