Author Topic: Electrical Update for The Thing in the Shed  (Read 8886 times)

Offline hopefuldave

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Electrical Update for The Thing in the Shed
« on: April 14, 2012, 12:53:16 PM »
Some pics of my electrical update - it got a bit more involved than I expected!

 :proj:

The VFD installation on my Holbrook was a bit of a lash-up (made by me, I freely admit!), so I bit the bullet and made a new electrical panel, with modern components (it's hidden away so it doesn't show!) and up to modern safety standards - no more exposed 415v terminals! (OK, I still have to make the "safety" cover for the Frankenstein switch, but it's in hand!)

The panel has circuit breakers for *everything*, contactors handling power switching, relay "logic" to make the original "coolant" push-button toggle the suds VFD on and off, connections for the original switchgear (with a couple of additions) and "ET's little brother", the VFD remote panel with motor-current meter, 3 speeds and variable control, worklamp switch etc. - all control circuits are now either 24v from the VFD or 24v AC from the control transformer, originally they had 415 running through them  :zap:

The original Frankenstein switch is retained for the 3-speed 415v motor, otherwise it just wouldn't be a Holbrook!

Both VFDs (spindle and suds) are located on a pull-out "drawer" in the base cabinet so they don't show - wanted it to look as original as possible! The panel itself fits in (I've checked...) the "bread oven" at the headstock end of the base, so they don't show, either!

Anyway, before and after (as far as testing on the dining-room table... Still have to tidy the wires and bolt it in, maybe this weekend!)

Dave H. (the other one)
Rules are for the obedience of fools, and the guidance of wise men.

Offline John Rudd

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Re: Electrical Update for The Thing in the Shed
« Reply #1 on: April 14, 2012, 01:02:47 PM »
Blimey Dave, you certainly went to town on that lot.... :clap:  :bow: :bow:

As someone who comes from an electrical/electronic background, I can appreciate how much time and effort has gone into your panel wiring... :zap:
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Offline Brass_Machine

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Re: Electrical Update for The Thing in the Shed
« Reply #2 on: April 17, 2012, 08:50:48 PM »
I know absolutely nothing about the electrical stuff. I wouldn't attempt it... if I did, I wouldn't be around long!

That is nice and clean thought. Very orderly.

Eric
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We're all mad here. I'm mad. You're mad.

Offline Stilldrillin

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Re: Electrical Update for The Thing in the Shed
« Reply #3 on: April 18, 2012, 02:10:59 AM »
Dave.
Very impressive.......  :thumbup:

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline Lew_Merrick_PE

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Re: Electrical Update for The Thing in the Shed
« Reply #4 on: April 18, 2012, 10:29:20 AM »
Ah, but where is the magic smoke release button?

Offline hopefuldave

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Re: Electrical Update for The Thing in the Shed
« Reply #5 on: April 19, 2012, 03:00:39 PM »
No MSRB[0] fitted, as such, but...

The Frankenstein Switch can't be operated[1] under power, as VFDs Don't Like That, but there are *lots* of MSCD's (Magic Smoke Containment Devices) built in! e.g. magnetic circuit breaker on the power input, one for the spindle VFD, one for both work lamp and motor cooling fan, one for the control transformer, one for the suds VFD - then there are interlocks that (f'rinstance) won't let me power it up with forward or reverse engaged, multiple E-stop and (spindle & suds) power-off circuits...

I added a few convenience touches too, like the fan and lamp power (and DRO once it's cobbled together) staying on unless I hit the machine isolator, suds switching on with spindle rotation (when "enabled" with the push-button), remote switch for the lamp located up on the VFD remote head... I just don't know when to stop, sometimes  :palm:

All in all, it seems to work how I'd want it to, even if it's a bit scruffy to look at!

Dave H. (the other one)

[ 0 ] Magic Smoke Release Button, of course!

[ 1 ] well, kinda can't -  the motor's a constant-3HP, 3-speed, 3-phase pole-switching BTH about the size of a dustbin, and I'm told the induced voltage spikes could kill the VFD if I go changing windings at speed? Luckily the VFD gives enough speed control (20% - 150% of chart speeds) that along with the (roughly) 4:1 speed change on the clutch/brake box I can do most things without changing motor config - for instance, at the extremes it gives me 4.4 - 33 and 18 - 130 RPM in the lowest motor config and backgear, 75 - 550 and 300 - 2250 in highest config direct  :)

It does lose a lot of power at low VFD frequencies, though, have to keep above 30Hz to the motor for heavy work :(
Rules are for the obedience of fools, and the guidance of wise men.

Offline velocette

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Re: Electrical Update for The Thing in the Shed
« Reply #6 on: April 19, 2012, 05:18:14 PM »
Congratulations Dave on a wonderful and well thought out conversion I have followed this post with great interest.

You have explained very well what this setup is capable of doing. A true marriage of old and new technology in the one of the best conversions in the true "Mad Modder" tradition.
 
Thanks  Eric