Re: Variac Help

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: BunnyKiller <bunikllr-at-bellsouth-dot-net> 



Tesla list wrote:

>Original poster: "EMMETT SECREST" <secrest2032-at-msn-dot-com>
>I am in need of help on wiring of a Technipower 30A Variac.  I purchased 
>it used and there are no instructions. I don't want to toast it as it was 
>a little on the expensive side so your assistance is appreciated.  It has 
>five connection points in this order;
>
>1  5  3  2  4
>
>1 = one end of the coil
>5 = between connection 1 and the center tap
>3 = center point of coil
>2 = between the center point and the end of the coil, point 5
>5 = the other end of the coil
>
>This is a 130 volt single phase model that mounts inside a cabinet of some 
>type and does not have it's own enclosure.. My question is which points 
>does the 120V supply connect to and which points are the output. Also 
>where would the safety ground connect.
>
>Thanks in advance for your help,
>
>Emmett
>
>_
>

Hi Emmett

there are 3 different ways to hook up that style of variac....

if you are using 120 +-10VAC...   consider black the hot lead  and white 
the neutral  and green the ground

setup #1
input power  -  120VAC white to #1 lug      120VAC black to #4 lug
    green to ground on item to be powered and to case of variac

output to item to be powered     white on #1 to item     black from #3 to 
item       green variac case to item ground
this produces 120VAC in  and 0-120VAC out  at 30 amps output



setup #2

input power - 120VAC  white to Lug #1    120VAC black to #2 lug
green to variac case and item to be powered ground

output to item to be powered    white on #1 to item    black from #3 to 
item     green from case to item
this produces 120VAC in and 0-140VAC out  at 26 amps output



setup #3

input power - 120VAC white to Lug #1   120VAC black to Lug #5     green to 
variac case and to item to be powered

output to item to be powered   white on #1 to item   black from #3 to 
item    green from varaic case to item to be powered
this produces 120VAC in and 0- 280VAC out   at 40% of variacs current 
rating   in other words   12 amps or so


do not pull more current for extended times shown above or the variac will 
get hot and become damaged     especially if you set it up as in case 
#3...  limit the current draw to 10A in setup #3 and it will be ok      BE 
SURE that item to be powered can handle the voltages in setup #2  and 
specifically in #3...


Scot D