Thread: VFD upgrade
As my chinese VFD just died I'm planning to get a decent one for my 2.2kw chinese spindle.
I've searched for them and now I have no idea what differences there are or what specs to look at? I've read something about vector speed but I don't understand it well.
I found Hitachi, LG, Lenze, Parker, Yaskawa, Bosch, Power Drive, Schneider, Moller .... and I have no idea what to choose...
Any suggestions/recommendations would be really appreciated.
This is a good place to deal with;
I like the ABB ACS355 drives but to be honest they had trouble getting it to work at the high frequencies our spindles use, they did get there in the end though and it's working great.
My spindle runs in vector mode because it gives high torque at low speed but if you don't intend using it at low speed then you probably don't need it. At very low speeds where you still want torque you would have to derate the motor, so for example you might have to use a 3kW spindle to get 2.2kW out of it at low speed.
The reason I use low speed (1000 rpm) is to drive sanding drums like these; http://www.axminster.co.uk/axminster...-sanding-drums you can turn the machine into an oscillating drum sander.
Last edited by EddyCurrent; 20-10-2014 at 05:09 PM.Spelling mistakes are not intentional, I only seem to see them some time after I've posted
Thank you Eddy,
Being able to run at low speeds sounds very useful.
Interesting point with the sanding drums but I cannot imagine running on CNC. How do you calculate/apply the sanding load. I can imagine a specially designed spindle mount fitted with springs or something.
Still trying to find the ABB inverter locally. So far I found the LG IC5. It has the vector mode but I found this in the manual:F21 - This parameter sets the highest frequency the inverter can output. If H40 is set to 3(Sensorless vector), it can be settable up to 300Hz *.
I also found the Schneider Altivar 12. Any thoughts about the LG and Altivar?
Last edited by paulus.v; 22-10-2014 at 08:05 AM.
Used like this only the sanding drum is held from above in the spindle collet, Z moves up and down.
Regarding settings for ABB, one of the main problems was getting the right technical data about the spindle motor, your spindle is not the same as mine so the settings I have will not be exact and I could not say for sure they would work. see here; http://www.mycncuk.com/threads/6565-...4303#post54303
Schneider Altivar is good stuff, used a lot in industry, you won't go wrong with those, don't know about LG.
Last edited by EddyCurrent; 22-10-2014 at 08:22 AM.Spelling mistakes are not intentional, I only seem to see them some time after I've posted
Now I get the sanding use.
I thought you have the 2.2kw chinese spindle.
I'm waiting for a price for the Altivar inverter. I think Schneider will it be.
Has anyone here experience setting up the Schneider Altivar 12 with the chinese 2.2kw spindle and Mach3?
Just to be clear, vector control gets rated torque down to low (zero with an encoder) speed - it doesn't increase the torque above rated at low speed, as that would exceed the ratings of the motor. This is important since power is the product of torque and speed, so with a constant torque vs speed characteristic the power is proportional to speed - so you only get rated power at rated speed. Or half rated power at half speed... etc
Last edited by Jonathan; 22-10-2014 at 10:05 AM.
I see that vector control is a good thing to have anyway.
From Wikipedia:Vector control, also called field-oriented control (FOC) was originally developed for high-performance motor applications that are required to operate smoothly over the full speed range, generate full torque at zero speed, and have high dynamic performance including fast acceleration and deceleration.
However, it is becoming increasingly attractive for lower performance applications as well due to FOC's motor size, cost and power consumption reduction superiority.
It is expected that with increasing computational power of the microprocessors it will eventually nearly universally displace single-variable scalar volts-per-Hertz (V/f) control.
No one uses the Schneider Altivar 12 with the Chinese spindle? I'm going to buy it and will see if I will manage to get it set up and working in vector mode...
I think if you need technical support then Schneider is a very reputable company and will provide it.
Just found this, it looks like ABB have looked at high speed operation a bit closer,
"Control program introduction
Application specific firmware for high speed grinding and polishing machines. Spindles can operate up to 1400Hz output frequency in scalar mode and up to 32000rpm in vector mode."
Last edited by EddyCurrent; 23-10-2014 at 06:03 PM.Spelling mistakes are not intentional, I only seem to see them some time after I've posted
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