AC servo motor help !

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Originally Posted by Jonathan

For peace of mind you could increase the size of the capacitors to compensate for single instead of 3 phase.

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Funny that you mention this... :-) On the PCB there is a foot print for 5 caps but only 4 fitted! Could add an exta one I suppose...

If in doubt as a last resort read the manual provided or if not supplied down load it from the internet or look on the internet to find out how other people have solved the same problem for that particular motor.

Assuming those caps and the "spare" are all in parallel adding another will increase the capacitance, so should do no harm. G.

grinorfrown?

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Originally Posted by m_c

If you do add another capacitor, make sure it's a similar spec to the ones already fitted, and that it's capable of a pretty large ripple current i.e. don't go for the cheapest one you can find, as if it can't handle the ripple current it'll overheat and go pop pretty quickly.

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Yes... I thought so... There must be a reason why this particular model of cap cost over £30 where you can find some of same value for less than £5.00 ! :-)

All caps are in parallel...

But, anyway I am pretty sure wiring the way I did (N, L, L) gives exactly the same work load to the caps and rectifiers as using 3 phase.

smilesmile

Hello to all!
I have a similar problem.. but with one advantage i have 3 phase 400V (not 3phase 230V servo needs)..

In europe the mains power supply is 230V 1 phase / 400V 3 phase 50hz.
I got a 3 phase servomotor + 3 phase servodriver 1.8kw 220V and i have to my house 1 phase 230V and 3 phase 400V what can i do to connect this servo ?
3 phase transformer from 400V to 230V would be ok ?
Can i run it from 1 phase 230V without transformers ?
The driver inside has 3 big 420V 270uf rubycon MXG(PET) capacitors ..
To use single phase supply without transformers If i add 3 same caps in parallel and connect phase to L1 terminal of driver neutral to L2 terminal and phase again to L3 will be ok ?
Can you help me ?
thank you.

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Originally Posted by vre

3 phase transformer from 400V to 230V would be ok ?

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Yes, but probably a bit expensive?

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Originally Posted by vre

Can i run it from 1 phase 230V without transformers ?
The driver inside has 3 big 420V 270uf rubycon MXG(PET) capacitors ..

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To operate with single phase continuously at the rated power you would need three times the capacitance - so an extra 1620uF. Keep the wires from the new capacitors to the existing ones short. Also check the current rating of the rectifier.

Bear in mind that if you're not using the servo drive near it's rated power, you may well be fine leaving it as it is. Have you tried contacting the manufacturer about operating on single phase? They might have already included enough capacitance to work with single phase.

Thanks for your reply!
I don't know the manufacturer the drivers are chinese copy Special AC servo motor 110ST-M06030 6N. M 1.8KW+ drive Kit line - iBuyLa_Tmall_Taobao Angent - Online Shopping at iBuyLa.com in Singapore .
I have oscilloscope so i can see the curve of voltage after rectification so i can find if smoothing is ok or not .
The enclosure of driver does not have space for extra caps so if i add more i will put them outside the drive.
The pcb has 2 rectifiers (4 legs each one) much be change them with bigger rectifiers ?

Some more questions..
How to connect the single phase to L1/L2/L3 of driver ? phase -> L1 , neutral -> L2 , phase -> L3 OR neutral -> L1 , phase -> L2 , phase -> L3 OR it doesn't matter ?
If 1 or 2 of rectifiers fails what other failure can be happen in the drive ?
Must change the rectifiers with bigger current rectifiers ? how much bigger ?
(I have an oscilloscope so i can see if voltage is smooth when i add extra caps)
My driver specs (from here http://item.taobao.com/item.htm?id=1...catid=50006522 ):
AASD 30A servo motor parameters
Rated current :0 - 10A
Rated Power :0 - 3KW
Rated line voltage: 220V
Peak Current: 30A
Rated speed :0 - 3000