800w spindle - noise & controlling remotely

[Boyan Silyavski]

Ok, the seller graciously let me off the hook :-) (lesson learnt - never buy when you're tired & don't trust the Ebay search....get into the detail!)

So ok, since I've now I've been won over into getting a VFD for me 800W water cooled spindle ....the Toshiba in Italy is 0.75KW OUTPUT ...& whilst i'll never upgrade the spindle that I have to a larger one, i do agree with jonathan that it's best to over spec (therefore buy a 1.5kw vfd) because the components will be rated higher & won't break out into a sweat. This leads me back to Chinese ....but there seems to be a huge number out there.

Is there any one particular model that I should seek out? (or avoid?!)

Some VFDs seem to be sent from Portsmouth...which appeals as I'd rather not wait 4 weeks to get up & running on my new machine purchase.

Manufacturers state that its Not OK to oversize or under size VFD . The maximum acceptable is 1 size bigger. I believe its because of trip sensitivity. Obviously 4.5 A rated VFD like the 800W can drive 1500w motor. As 800w spindle consumes 2-2.5A in reality and 1500w motor consumes 4A.

So in fact there is no need at all to oversize VFD as they are strong enough for 10 years non stop use as i remember from the specs. You should check though the manual if you decide to oversize. Need to check if you can program all the parameters of your current motor, like current draw, size, etc. cause what is the point of getting bigger if it could not drive properly the motor you have. Cause i believe certain manufacturers will not permit programming of smaller motor.


Also to avoid further mistakes, find the specs of your motor. Check at what voltage and what frequency is driven! The VFD i recommended you drives 3 phase motors up to 400HZ at 230v. Check if your motor is 200, 300, 400hz or even more and if 230 or more volts. This is very important so you can couple it correctly with the VFD.

[HankMcSpank]

Also to avoid further mistakes, find the specs of your motor. Check at what voltage and what frequency is driven! The VFD i recommended you drives 3 phase motors up to 400HZ at 230v. Check if your motor is 200, 300, 400hz or even more and if 230 or more volts. This is very important so you can couple it correctly with the VFD.

Thanks for your input (it really is appreciated), re the spindle, I will try & establish more info about it, but the seller said that this was the original VFD that came with it....

VFD Inverter 2HP 1.5KW 4 Spindle Motor 1/3Ph In-3P Out | eBay

[Jonathan]

I agree there's not much point oversizing if you're getting a VFD from a reputable manufacturer - unless maybe it's being operated at an unusually high temperature. You'd be fine with the 0.75kW Toshiba VFD as you'll struggle to draw full power from the spindle, and the worst that can happen if you do is the VFD will just cut out to protect itself. It's better to select the inverter by current rating, not power rating.

The VFDs from China let you set all the relevant parameters, like current and voltage, accurately so there's nothing to worry about there.

Plenty of the 1.5kW VFDs available for £86:

http://www.ebay.co.uk/sch/i.html?_so...D&LH_PrefLoc=2

Maybe less if you use best offer...

[Boyan Silyavski]

I agree there's not much point oversizing if you're getting a VFD from a reputable manufacturer - unless maybe it's being operated at an unusually high temperature. You'd be fine with the 0.75kW Toshiba VFD as you'll struggle to draw full power from the spindle, and the worst that can happen if you do is the VFD will just cut out to protect itself. It's better to select the inverter by current rating, not power rating.

The VFDs from China let you set all the relevant parameters, like current and voltage, accurately so there's nothing to worry about there.

Plenty of the 1.5kW VFDs available for £86:

1.5kw VFD | eBay

Maybe less if you use best offer...

Thats what i was just going to tell. GOOD 2HP 1.5KW VARIABLE FREQUENCY DRIVE INVERTER 220-250V 7A VFD o4 | eBay

The one from his link is 380V and 230v input, that's why is more expensive than the 230V input.

[HankMcSpank]

The braking resistor (referred to in the drawing in this advert - HIGH QUALITY NEW 2HP 1.5KW 7A 220-250V VARIABLE FREQUENCY DRIVE INVERTER VFD T2 | eBay ) ....presumably this slows the spindle quicker when the spindle is stopped - is the resistor needed (in other words does the spindle take forever to stop without it)....is it as simple as a large wattage resistor...and what's the spec typically used for the braking resistor? (on the toshiba it said "braking module available separately" ....which suggests it'll cost a pretty penny!)

[Jonathan]

You don't need a brake resistor as the spindle will stop in a few seconds without it.

[Boyan Silyavski]

However its a good idea to program ramp time of 6 sec in the Vfd and 10 sec dwell time in Mach3

[HankMcSpank]

for what it's worth, this seems to be the spindle I have...

800W High Speed CNC Spindle Motor, View spindle motor, JST Product Details from Changzhou Jiesite Electrical Co., Ltd. on Alibaba.com

(the model is jgd-65c-800 - it has 400Hz stamped on the case)

[Jonathan]

In my first post when I talked about getting the higher quality version of the 800W spindle to reduce noise (among other things), I didn't realise that you already had a spindle. I've made the video comparing the two spindles I have to hand:



Again, the video makes it sound worse - in reality the 3kW spindle is so quiet that you could almost forget that it's switched on.

[HankMcSpank]

Thanks Jonathan...quite a difference - even with the 3kw spindle lying on a large flat table (which will possibly 'amplify' the spindle's sound/vibrations ....just like a soundbox on an acoustic guitar).

The smaller spindle sounds quite loud to my ears...but again, that might be a trick of the camera mic.

(btw your audio in that youtube video drops out completely at approx 4m16s)