800w spindle - noise & controlling remotely

Ok, I now have a machine that came with a 800w water cooled spindle (it's a used machine & didn't come with a VFD...presumably because the VFD went the way of 'he no workee')

I'm having severe doubts about even buying a replacement VFD, becuase...

1. The 800w spindle seems stupidly heavy for the size of this 3020 machine (& I'd rather have a zippy Z axis)

2. Water cooling just seems like a hassle (especially when my CNC sessions are typically 30 minutes to mill a pcb!)

3. I only ever mill pcbs (1.6mm thick fibleglass boards) and 5mm acrylic (never metal!)

but mainly because....

4. Every youtube video I've listened to, makes these water cooled spindles sound like jumbo jets taxi'ing down a runway (& I thought the unique selling point for these spindles was lower noise!). Jonathan's video helps my quest - http://www.youtube.com/watch?v=xciLCN2Dz08 but it sounds loud ....like erhm 'put that darned thing in a detached garage at the bottom of the garden' type of loud ...but once again, the camera is very close to the spindle)!

With this latter point in mind can anyone give me their thoughts on how loud their water cooled spindle sounds turning at say 12,000rpm?

My sensitivity to noise is because my CNC is in our house (in our dining room, you never hear anyone say "could you pass to the ketchup please", but rather "could you hand me a 3.175mm ball tip endmill please") ....my wife isn't at all happy about this arrangement (alas, "Oi woman ...know your place", hasn't had quite the required effect) & having the sounds of a jet turbine within earshot of Eastenders isn't going to strengthen our relationship! I'm hoping that all these aforementioned youtube videos sound loud because typically the camera gets *real* close to the spindle & therefore the mic gets real close to the spindle ....but how loud does a spindle sound at a couple of metres? (I realize this is subjective & perhaps unreliable, but nevertheless I'd welcome your comments. I actually rather fancy one of these in place of a water cooled spindle....

http://www.amazon.co.uk/12v-52v-Air-.../dp/B00CM5WCNO (i.e. a 2013 updated 400W version of the standard 300W spindle that's particularly ubiquitous in the budget CNC world)

With respect to controlling the speed & turning the VFD on/off....again, most videos I've seen, see the VFD mounted on a wall or pillar near the operator & then they press buttons on the VFD to start stop the spindle (what a drag) ....well if I went the way of a VFD, it would go in the CNC control box...so how much of an ordeal is it to control the VFD remotely (I'm thinking here by the CNC app ...how is the speed set remotely ...PWM? Some serial protocol?)

What we need us for people to use the sound meter app on their mobiles and measure the actual dBa level 1m from the spindle at a known rpm, say 10k

Most VFD have a 'run' input that can be driven by a BOB output. The speed input to most VFD is a 0 - 10v analogue signal that some BOBs can output.

As you probably guessed, the reason I spoke in the youtube video you linked to was so that you could set the volume so that I'm speaking at a normal volume, and judge the noise from the spindle accordingly.

I doubt the spindle from amazon will be quiet as it has a fan on the end, so there will be noise created by the airflow. This is unnecessary when you can quietly water cool it. Don't be afraid of the water cooling - it can be simple and easy.

If you go for one of the better quality (and much more expensive) water cooled spindles, I'm pretty confident you'll find it's a lot quieter than the standard 2.2kW ones. The one I used here is that type, and I recently obtained a 3kW one on eBay for the right price which is even quieter:

Attachment 10022

Admittely it's a bit on the large size for your machine, but I expect the 0.8kW one isn't going to be worse. Also you'll get much lower runout (a few micrometers) with these spindles, which could be an advantage if you're cutting a particularly detailed PCB. I can post a video with them both switched on one at a time if you want to compare?

Edit: Unfortunately I don't have a new enough phone to measure sound level.

P.S. Where about is 'on the move'? Clearly the best way is for you to actually listen to one - you're welcome to pop round...

Re the air cooled 400w spindle ...I've presently got a 300W version & whipped the fan of it....it's stupidly quiet (but obviously I can't run it for long!)

Yeah, your new/improved spindle is way too big for my modest machine.... 'on the move' is actually London (I was about to move to Dorset but it all went pete Tong - still might), but nevertheless, thatnks for the offer but it's a little bit too far to come & have a listen.

Perhaps I'll just pony up for a VFD & just run the spindle at lowers RPMS if the noise is too prohibitive.....

I have 800w watercolled spindle and honestly its the quitest thing in my garage. The router bit itself makes 50x noise when routing. if your breakout board do not suppost output of 0-10v the next best thing to do is attach to an available output this board c41

Dont be put off the spindle, you want be disappointed. They sound like jets, due to the microphone autolevels of the cameras or phones with cameras used making the videos. In reality, you can not hear it next room.

Instead of spending money on radiators, you can follow my advice on the other thread you started and use the money for the C41 PWM control. Once you set up the frequencies you forget about this. Look at the picture of my setup on the other thread you started http://www.mycncuk.com/forums/router...s-buckets.html . See that paper just above the computer, ticked to the wall? That was from the time i was not controlling it via the C41. Every time i had to set up the frequency responding to measured RPM. Its a table of frequencies and responding RPM.
Now i have my tool database in Aspire programmed, so the CAM exports the G code and mach3 picks up the RPM from the G code and commands it directly. One less thing to worry.

Even if Dean /Jazzcnc/ pointed at one other thread that the chinese VFDs are getting better every day, if i were you i would buy this one INVERTER VETTORIALE TOSHIBA 0,75 kW 230 Volt MONOFASE USCITA MOTORE TRIFASE 1 HP | eBay

Another benefit versus 300w one is that if your machine is rigid enough or not , with very light passes you can do aluminum. At this point you will run it at 3000RPM so 800w spindle is quite more stronger than 300w at low RPM. And as they pointed to you, the run out is very small. I doubt that the 300w one comes with four bearings like the 800w.

Pointless seeking advice if I don't act upon it, so upon your recommendation, I've just this minute pulled the trigger on this VFD...

toshiba vfnc3s-2004pl inverter | eBay (which is what the model that you linked to)

Toshiba are normally a good make, so I'll take a leap of faith here!

I think just to get up and running, I'll go with a passive option (pump & a bucket - I'll get slick later)....has anyone a recommendation for a quiet suitable water pump

Quote:

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Originally Posted by HankMcSpank

Pointless seeking advice if I don't act upon it, so upon your recommendation, I've just this minute pulled the trigger on this VFD...

toshiba vfnc3s-2004pl inverter | eBay (which is what the model that you linked to)

Toshiba are normally a good make, so I'll take a leap of faith here!

I think just to get up and running, I'll go with a passive option (pump & a bucket - I'll get slick later)....has anyone a recommendation for a quiet suitable water pump

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Hey, wise choice. Hitachi also are good but in EU Toshiba is best priced.

NOTE: VFNC3S-2004PL. Toshiba Tosvert VF-nC3 Inverter for 0.37kW (0.5HP) 230V

The one i recommended you was the 2007PL for the 0.8kw

Did you make a mistake or bought this on purpose for your smaller motor?

Quote:

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Originally Posted by silyavski

Hey, wise choice. Hitachi also are good but in EU Toshiba is best priced.

NOTE: VFNC3S-2004PL. Toshiba Tosvert VF-nC3 Inverter for 0.37kW (0.5HP) 230V

The one i recommended you was the 2007PL for the 0.8kw

Did you make a mistake or bought this on purpose for your smaller motor?

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oops....that what I call a F*&% up!

I searched Ebay UK for the model in the italy ebay ad you linked to ...and Ebay returned the one I've just bought...I overlooked that model number difference! (heaven knows why it was returned in my search)

I've emailed the seller, hopefully we can cancel the transaction!!

If your concerned about getting the Chinese VFD, which I wouldn't be, bear in mind if you get the 1.5kW or 2.2kW version and run a spindle rate for only 800W then it's always going to be operating at a tiny fraction of the rating. This means it's not going to get hot, and heat tends to be what wears out electrical components. Also, plenty of people here use them so it's guaranteed to be easy to set up.

Quote:

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Originally Posted by Jonathan

If your concerned about getting the Chinese VFD, which I wouldn't be, bear in mind if you get the 1.5kW or 2.2kW version and run a spindle rate for only 800W then it's always going to be operating at a tiny fraction of the rating. This means it's not going to get hot, and heat tends to be what wears out electrical components. Also, plenty of people here use them so it's guaranteed to be easy to set up.

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I agree but there are 3 main points where i am not happy with Chinese VFD:

1. The documentation

The Toshiba VFD has 300 pages manual and every detail is explained in even greater detail. Its quite exhausting to program the VFD for one that has no idea on what it does exactly. I remember spending a week programming my first VFD. Now imagine the ammount of forums that have to be read to learn the same for the Chinese VFD


2. Warranty

Warranty in EU, not China


3. Price

For a 120eur for the 800w ones for me its a no brainer. However the Chinese one could be interesting in the 2.2-3kw range

Anyways, depends from the point of view. Every machine has critical parts and for me the VFD is one of the most critical. For example i use many of the functions of the said VFD. Like detecting stall and similar and tripping above a pre programmed amperage draw. The enable on my BOB is driven by the VFD. I leave the machine sometimes do long jobs. The machine is powered by 1500w UPS power supply. So if the electricity stops, if the VFD is not connected to the BOB, the machine continues doing whatever it does for half an hour more but the spindle does not rotate, imagine the mess and damage. Sometimes a bit breaks or digs and instead of damage, the VFD trips. i dont know of the functions of the Chinese VFD which possibly are the same. Just like playing safe, at least for a 800w spindle. For my next machine i could also contemplate 3kw chinese kit due to price.

Quote:

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Originally Posted by HankMcSpank

oops....that what I call a F*&% up!

I searched Ebay UK for the model in the italy ebay ad you linked to ...and Ebay returned the one I've just bought...I overlooked that model number difference! (heaven knows why it was returned in my search)

I've emailed the seller, hopefully we can cancel the transaction!!

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They have best price and 3 year guarantee + technical support if you have questions.

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.

When I was working in industry ABB was always my first choice for drives, I have one on my overhead pin router. I've never used the Chinese ones but there is usually a parameter for switching frequency, not the same thing as output frequency, this can reduce the noise coming from a motor.
http://www.danfoss.com/NR/rdonlyres/...eReduction.pdf

Quote:

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Originally Posted by HankMcSpank

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.

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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.

Quote:

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Originally Posted by silyavski

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.

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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

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...

Quote:

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Originally Posted by 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:

1.5kw VFD | eBay

Maybe less if you use best offer...

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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.

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!)

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

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

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)

The braking resistor is mostly for when a motor is connected to a load, for example imagine a motor connected to a 10ton flywheel and somebody hits the emergency stop button. There's a lot of energy to get rid of in a short space of time and it's the resistor that dissipates this energy, obviously a spindle in our application does not have a load connected.
Also re. ramp times, in the ABB I use on my pin router I have the normal ramp time set to something over 5 seconds (can't quite remember) but I can set another ramp for emergency stop situations and this is set lower and for this I use a braking resistor (because I already had one) which allows it to stop very quickly but in reality it's not doing a lot. Also the resistor is there to prevent damage to the drive, depending on how much protection is built into it the DC link voltage can rise and cause damage.

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:

http://www.youtube.com/watch?v=NH_w2...ature=youtu.be

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.

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)

Quote:

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Originally Posted by HankMcSpank

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

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Hmm, that's annoying as I just deleted the original so it'll have to stay like that. In the rest of the video I put the radio on again to demonstrate how you can't hear it with the old spindle running and also commented that it's all a bit insignificant compared to the noise generated when cutting unless perhaps what you're cutting uses very small/light cuts.

Quote:

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Originally Posted by Jonathan

Hmm, that's annoying as I just deleted the original so it'll have to stay like that. In the rest of the video I put the radio on again to demonstrate how you can't hear it with the old spindle running and also commented that it's all a bit insignificant compared to the noise generated when cutting unless perhaps what you're cutting uses very small/light cuts.

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No worries you went above & beyond the call of duty - pont taken about the noise of the actual cutting itself, but for me it's mainly gonna be just 0.1mm deep into FR4! (so the noise of the spindle is likely to be the main contributing factor wrt strained man/wife relationships!)

So, something arrived in the post today, from Italy ...

http://hostmypicture.com/images/tosh.jpg

...yay!

About £120 delivered (thanks for the heads up silyavski).

Sure, I can buy cheaper if I go the Chinese path, but I've had some horrific experiences with chinese electronics over the past couple of years (TB6560 anyone?), so I decided to pony up the extra forty quid which will hopefully save me some grief!

Quote:

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Originally Posted by HankMcSpank

So, something arrived in the post today, from Italy ...

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Great so is it running yet.? . . . . If not why not. .:eagerness: . . . .Think you'll like it.!!

A bit more heads up:

The Speed and corresponding frequencies in HZ, measured carefully with a device, you r can be slightly different but not so much. Open it in new window to see it better and enlarge it with "control" + "+" , or PM if you can not read it:

Attachment 10396



The typical connection / check well the manual/

cables from left to right
- trip ,
- PWM control,
- ??? i forgot , not so sure, but it was enable to the BOB, in case of power loss it stops everything/

Attachment 10397

Looks like section 6.18.3 shows how to configure the display to show motor speed.

Quote:

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Originally Posted by JAZZCNC

Great so is it running yet.? . . . . If not why not. .:eagerness: . . . .Think you'll like it.!!

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Unfortunately I'm not going to get a chance to wire it up for a little while yet :miserable: (probably some time over the weekend)....got to think this one through & decide just how 'integrated' (wiring wise, remote control, speed control etc) I want to make it for my present or predicted method of working.

I'm figuring most folks have their VFD actually mounted near the machine?

The non-working machine I bought had its VFD tucked away in the 'enclosed' control box (well that is, before the VFD stopped working & they removed it!)

Quote:

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Originally Posted by HankMcSpank

I'm figuring most folks have their VFD actually mounted near the machine?

The non-working machine I bought had its VFD tucked away in the 'enclosed' control box (well that is, before the VFD stopped working & they removed it!)

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I prefer to have it near machine so can see the Amp's it's pulling while cutting. I set the RPM then display Amps and just have Start/Stop under machine control.

Oh dear....what is it about the CNC genre?!!!

So I've just hooked up my new VFD to my 800W spindle - the VFD is tripping outwith an overload condition.

I'm figuring it's likely to be the spindle becuase it's of unknown status. I bought the CNC machine in a "needs putting back together" condition ...with a VFD missing. I'm now assuming that a spindle fault perhaps took out the original VFD?

I'm controlling the spindle speed manually with a 10k pot that I've connected up to the VFD, I can get the spindle to turn very, very slowly (without tripping) with the pot at its lowest speed setting but if I turn the pot just a degree or two the VFD goes into an error condition 'overload'....I've checked the VFD settings for tripping out (they're all at default...and nothing seems untoward there)

I don't suppose it's easy to test these water cooled spindles? (I'm seeing just a couple of ohms between pins ...also when the spindle is turning even ridiculously slow, the spindle outer chassis gets warm (not ouch warm, but warm...which is surprising bearing in mind it's turning very slowly ....like 60RPM or so)

Any ideas?

VFD will trip on over current or over voltage. If the spindle is getting hot with no load, that means the current is too high. For there to be too high a current the voltage the VFD is applying must be too high (ohms law), so check what the voltage is at rpm.

The vfd, when using vf control, should increase the voltage proportional to the frequency, so (generally) rated voltage at rated speed, half voltage at half speed etc.. What might be happening is the voltage/frequency curve is set wrong, so it's applying much too high a voltage, which in turn causes too much current to flow, so the VFD trips.

Possibly as suggested by Jonathan, wrong programming of the VFD. Its a very long manual, i know. But is unavoidable. Follow it step by step.

Check the phases on the motor! Wait for the VFD untill the led goes out after disconnecting before you touch anything!

The spindle can work hours without water without heating.

You don't need a pot right now. The button on the VFD rotates and you change the frequency.

Read the manual. the VFD stores last trips, you can go there and check what happened exactly, so no need to measure anything. During operation you can also monitor A, V and so on calling them on the display with a button.

well, I've had a bit more dabble with some of the VFD parameters. I found the base frequency voltage setting (which was set to 230V ...Im assuming this is the max peak to peak height of the pulse train that the VFD puts out?)

Anyway, I set it low (right down to 60V)....but the VFD is still tripping with an overload condition (& I noticed a peeeoooo space invader type sound eminating from the inside spindle itself just before the VFD trips, but this might be the VFD shutting down causing that sound).

there's surprisingly little info out there about typical winding arranbgement & readings for these spindles (like I say I was reading 3 ohms between pins which seems stupidly low, cos if my calculations are correct DC output of 230V, will yield an RMS Voltage of 84V which infers 28Amps!! (but there again, I could have all this wrong!).

Also, back to the spindle internals....does anyone have a link to a diagram of the typical coil arrangement inside?

I'm 80% certain it's the spindle...begs the question has anyone upgraded & got an 800W water cooled spindle lying around they wanna sell?!

Quote:

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Originally Posted by silyavski

Read the manual. the VFD stores last trips, you can go there and check what happened exactly, so no need to measure anything. During operation you can also monitor A, V and so on calling them on the display with a button.

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Alas, the menu structure, naming convention (& indeed the manual itself), is anything but intuitive!

Just the base frequency setting isn't what you need, as that's the voltage at the rated frequency (400Hz), but we need to know the voltage across the whole range. Have you checked that the frequency this voltage refers to is definately 400Hz, as if it's 50Hz that would explain what's causing the problem, as it means the VFD is applying 8 times the required voltage at 50Hz.

You're correct in saying that a DC output of 230V would imply a very high current (although it's not 230V DC, 84V or even 28A), but fortunately the VFD outputs AC not DC! The impedance of the spindle increases with the frequency applied. You can think of impedance as resistance, but for an AC circuit with inductors/capacitors. So at 0Hz (DC) the impedance is equal to the DC resistance you measured (3 ohms, which sounds about right), but as soon as you increase the frequency the impedance increases proportionately. It also changes with load. That's why as the frequency increases you need to apply a higher voltage to be able to output the same torque. So in short your measurement implies that the winding's aren't burn out, but it's nowhere near enough to say if the spindle will work.

Quote:

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Originally Posted by HankMcSpank

Alas, the menu structure, naming convention (& indeed the manual itself), is anything but intuitive!

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Strangely the translated chinese manual for the VFDs most people get to control their spindles are easy to understand.

Have you got skype? If you're sitting there with the VFD we can probably sort this out in half an hour...

Didn't spot this bit...

Quote:

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Originally Posted by HankMcSpank

Also, back to the spindle internals....does anyone have a link to a diagram of the typical coil arrangement inside?

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It'll be one of these:

Attachment 10421

Just to be clear, you did check that the 3 resistances are the same? If off by more than about 10% (complete guess) then you've got a problem.

Quote:

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Originally Posted by Jonathan

You're correct in saying that a DC output of 230V would imply a very high current (although it's not 230V DC, 84V or even 28A), but fortunately the VFD outputs AC not DC.

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I did some speed research earlier...my interpretation may be incorrect, but I thought these VFDs put out a PWM pulse stream (& relies on the inductance of the spindle coils to essentially filter the VFD output pulses & restore a sine wave from them - similar to filterless class D audio amplifiers). If that the case, then the aforementioned 230V output, will be the maximum peak to peak level of the restored sine wave)

Quote:

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Originally Posted by Jonathan

Have you got skype? If you're sitting there with the VFD we can probably sort this out in half an hour...

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I have skype, which I seldom use & I can't immediately lay my hands on my webcam - if I find it I'll give you a shout on here :-) (but missus has furrowed brow which roughly translates into "you must not pursue this anymore this evening!")

My VFD manual is here...

http://www.mototecnica.eu/ebay/Inver...ng%20VFNC3.PDF (great for sleep inducement at this time of night!)