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Joint hogger

JH's Modded Basic Variac Controller

31 posts in this topic

Hope everyone's sitting comfortably, have a joint rolled & are sitting with a hot cuppa :skin_up:

as i had to strip my veg cabinet of my basic variac controller & use it elsewhere, i needed to get another controller

to replace it with as i've decided to reinstate the veg cab as my next grow will be something special :wink:

as its for a 5" ruck fan & 5" rhino combo, a 0.75A variac is ideal & i happened to have one spare as i'd stripped my twin variac build,

though the previous controller was ideal for my needs, i decided to mod this build it a bit.

so the parts i used -

AE 0.75A variac - £30 (bought 4 or 5 yrs ago)

ABS enclosure box CL (150x110x75) - £12

2 20mmx1.5mm cable glands - £2.50

1m of 1.5mm 3 core cable - £1

1 13A plug - £1.50

1 gang trailing socket - £4

2 inline fuse holders & fuses - £5

1 16A/250v SPST rocker switch - £1

1 AC analog panel voltmeter - £5

crimp terminals & connector block - £5

with a grand total of = £67.

right, on with the pictorial from start to finish.

heres the AE 0.75A variac dimensions & wiring guide.



& heres the enclosure box, it measures 150 x 110 x 75 & is slightly smaller than the enclosure box i used in my basic build.

i had to pay extra as i got a box with a clear lid, i also had to cut the mounting points off inside the box so they didnt interfere

with the brush arm on the variac.




i then cut 2 20mm holes in the base for the cable glands with a 20mm flat wood drill bit.


heres the glands fitted, you'll also notice the green switch on the lid, thats the 16A/250v SPST rocker switch * (Single Pole Single Throw)


heres some info on the rocker switch.



& heres how the switch works.


heres the variac fitted to the lid, with a 0.75A & a 1A variac, the dial is held on to the variac with 2 screws, the 2A doesn't have any

mounting holes for the dial so you might need to use superglue to hold the dial on.


heres the rocker switch fitted.



here i've connected the Live out from the rocker switch to the variacs Live in, i've also used inline fuse holders with 20mm A/S 800ma

quick blow fuses on the variacs Live in & Live out.


heres how to wire up the fuse holders :wink:


tbc :skin_up:

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heres another mod i've added to the plan, its a 300v AC analog panel voltmeter & its connected to the variacs Live out,

that way i can see instantly what the Live out voltage is in comparison to the variacs setting.

for the hole i needed to mount the panel, i needed a 34mm cutter but the cutter & a arbor would cost about £15,

so i used a 32mm flat wood cutter drill bit & a stanley to widen the hole up to 34mm, its a bit rough but it'll do.


heres the voltmeter & how to wire it.





heres the voltmeter fitted onto the lid.



& this is how it looks pre wiring.


this is the wiring before i add the Live in & Live out cables,


heres the wiring with in the Live in & Live out cables connected, just need to tidy it up & screw the lid on.


the finished article.


heres the SPST switch on but the variacs set to 0% power, im a bit disappointed with the switch, the lights orange colored & i wanted a green light, damn it :rofl:


Variac set to 25% - 60v output on the voltmeter.


Variac set to 50% - 120v output on the voltmeter.


Variac set to 75% - 180v output on the voltmeter.


Variac set to 100% - 240v output on the voltmeter.... :trumpet:


heres the design i used for the wiring.


now just to fit it in the cab & it'll be job done :yep:

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Ok sold ill buy it :wassnnme:

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Nice work JH :yep: I like the voltmeter, great idea

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like the voltmeter realy cool where did you get it from?

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amazon has them for less than a £5 or theyre slightly dearer on ebay, just be careful that if you do order one, make sure its the AC version :wink:

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time for a slight update, i've copied the modded variac but have used a slightly bigger enclosure & upped the variac to a 1A,

i'll only be running a 5" fan initially but might up it to a 6" L come summer, i might run the light on a 600 but i might also splash out on a couple of 315w ;)

anyway, back on topic. for the build i've used a ip65 abs plastic enclosure

(measuring L 300mm x W 220mm x H 125mm outer diameter) (inner diameter L 296mm x W 216mm x H 118mm )

1 x 1A ravi open variac, 1 x 270w analogue volt meter, 4ft of 1.5mm 3 core cable, 1 plug, 1 trailing single socket, 2 20mm cable glands,

a pack of insulated 6.3mm female lucas crimps & an illuminated 16A on & off toggle switch.

so after cutting & drilling all the holes i needed, i gave the box a blast of black spray paint, looks ok'ish but i messed it up a bit :doh:

so i started off by fitting the toggle switch to the lid, then the analogue voltmeter.

1A Fan Controller (1)

1A Fan Controller (2)

1A Fan Controller (3)

1A Fan Controller (4)

then a screwed the variac to the lid & then started on wiring my live in feed (15" of black 3 core cable) with a 1A fuse in the plug & my Variable Live Out to the trailing socket.
I also marked the variacs dial with a red marker at the 40% minimum mark so its easy to spot :yep:

1A Fan Controller (5)

1A Fan Controller (6)

1A Fan Controller (7)

1A Fan Controller (8)

next i started wiring from the Live in to the toggle switch then to the variac then to the Live out connector block
& then run a separate Live & Neutral line from the voltmeter to the Live out connector block, then i tidied the cabling up with small zip ties.
also just to point out, you have to combine the Neutrals on the toggle switch & on the variacs Neutral.

1A Fan Controller

1A Fan Controller

1A Fan Controller

1A Fan Controller

heres everything tidied up & ready to screw the lid on & test it, then it was screwed to the wall & set to 40%,
you can see the voltmeter & its at roughly 96v, just need to finish the fan's Leepy box & every things good to go :skin_up:

1A Fan Controller

1A Fan Controller

1A Fan Controller

1A Fan Controller

the only thing else i might do is add a couple of inline fuse holders for either side of the variac to be doubly sure of electrical safety & maybe add a STC-1000 thermostat ;)
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@@Joint hogger

Always enjoy reading your builds mate, nice work in here :yep:

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JH is an absolute credit to the growing community.Thanks for sharing.

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Nice work @@Joint hogger. Just wondering is the STC 1000 pretty much the same as the STC 800+ but cheaper?


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the stc1000 is an ok controller but the atc800 has a better LED screen ;)

just in case you dont know but theres a newer inkbird ITC-1000 available (stc1000 replacement) at roughly the same money & can do both celsius & fahrenheit :yep:

inkbird Itc   1000

or theres a newer update itc-2000 :yes: which is even better :yep:

inkbird Itc   2000

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Thanks, Informative and easy to understand,( well 'ish for me :) ). And thanks for the clear piccys. This is something ill come back to time and time again. ( sounds a bit crawly bum lick that :rofl: It aint meant to, but i know the time it must take to do all the pics etc . Dedication ( Wheres Roy Castle when ya need him :trumpet::) ))


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@@Joint hogger cheers mate, I have an ATC-800+ on my Variac controller that I built when I first got on here inspired by your good self and Laphroaig. The two units looked pretty similar so thanks for posting that info. I have a basic Variac I use to control my veg fan but thinking of upgrading to one similar to the flower rooms with a thermostat :yep:

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Old but Thanks for the variac threads @@Joint hogger ive made a few now based on yours.

Heres the latest design, just needs connecting.


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Very nice @Key4

hope you added fuses internally on the variacs live in & live out ?

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