[SOLVED] urgent:: connecting 3phase 220v motor

[Electro nS]

i have a machine (chinease) , the motor of it is is labeled 3phase 1HP 220v 60hz ,4pole , 3.8A
the wires coming out of it are 4 wires L1,L2,L3 and PE(yello-green) , i found an exact motor but with higher power at ebay : **broken link removed**

the measured electricity in my shop is 380 from phase to phase and 220 from phase to neutral or earth at 50hz

does the motor run directly or on this . or do it need a different 3phase ( 220v from phase to phase ). is this same naming ? or should i buy a transformer from 380v 3ph to 220v 3ph ??!! i am totally lost and a newbie to this kind of staff.

please help

 

[chuckey]

You have 380 3Ph. and 220 single phase.
You have chinese machine with a 1 HP 220V 60 HZ motor with L1,L2,L3, and earth.
Do you want to replace the above with the E-bay motor? Do you want to use the 220V motor on your 3 Ph. If so, open up the terminal box on your motor and see how many terminals there are in it and how they are connected.
Most 3 Ph. motors can be wired for 380/415V OR 220V. The windings are actually rated at 220V, so a winding across each phase (delta) gives you a 220V 3 Ph. motor. If one end of each winding is commoned to every other winding ("the star point"), with the free end of every winding going to the mains, then it can be used on 380/415 V 3Ph. Star connected.
Frank

 

[Electro nS]

thank u very much , i want to use my motor on my 3phase 380v , which as i understand from u is not the same as the motor.

now what you said makes sense because the motor electrical box says : " Prewired 220v " and after opening that box , there are 2 ways of wiring drawn , one of them that is used (after checking by multimeter) called : "2Y and low volt" the second is called "Y and High voltage" . so simply i should change the wiring to the second called Y , please check figures and pics attached and correct me if i am wrong ??






this is a similar diagram found online , i think this is the motor i have : 9 wire wye connected , can be run on high and low voltage by changing the wiring , check it please i donot want to burn the new motor !


i appreciate your patience.

 

[schmitt trigger]

In the photo of your motor, you have a label. Wire it as indicated for "high voltage" and it will work.

The diagram you found online is similar, but has different wire nomenclature...disregard it, it may confuse you.

But indeed, it shows how you can wire a motor in delta or wye for 220v or 380v respectively.

Now, for your chinese motor...it is rated for 60 Hz. At 50 Hz it will run slower than the nameplate RPM. Is that ok?

 

[D.A.(Tony)Stewart]

Magnetic Core saturation is a function of V/f so this ratio must not be exceeded. In your case V should be 183Vac for 50Hz.

If the lower RPM is acceptable, ensure V/f is not exceeded in your transformer selection and accept that you will not get rated HP out due to excess heat from Excitation currents which are much higher than this frequency ratio from saturation.

unless you choose a Motor Generator system that converts both V and Hz

If the design had 15% more windings it could have the same V/F B field in the core to operate a 60Hz motor at 50Hz

 

[schmitt trigger]

You are absolutely correct, skinnyguy. Saturation is a concern for a 60 hz motor operated at 50 hz.

The easiest would be to employ an autotransformer to step down the voltage to 315 volt. But then actual RPM and HP would only be 5/6 of the nameplate ratings.

 

[D.A.(Tony)Stewart]

Good idea Smittentrigger.

I think a 3ph 2KVA Autotransformer runs around $300 and weighs 10kg.

j/k :wink:
Sunny Sky

aka "Tony" Stewart

 

[Electro nS]

thank u i rewired as the specified diagram and it works flawlessly (hopefully) , i can tolerate the decrease in speed

i will mark as solved

 

[D.A.(Tony)Stewart]

I wonder if Electro nS cares about the higher conduction losses from much higher excitation current?

 

[Electro nS]

i donot know what that is and i really donot care , since this is the only way am going to run this machine , hopefully next time i will buy a better product that suits my electrical system . but thanks anyway all who helped