Variac
Continu^&Wy^A&jUstabie Autotrârisformer for Control of A-C Voltages Wherever ordinary a-c power lines are available, the Variac is useful for controlling VOLTAGE . . . HEAT . . . LIGHT . . . POWER . . . SPEED. The Variac is popular because it can be used by anyone, in almost any location on a wide variety of jobs. It operates from standard 115 or 23Ό a-c line voltage to provide any output from 0 t o ' 1 7 % above line voltage . . . for controlling the operation of practically any de vice powered by electricity. Operation is extremely simple. A single knob con trols the position of a continuous, sliding contact, running on the circumference of a toroidal winding. The sliding tap determines the portion of the line voltage made avail able at the output terminals.
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Regulation is substantially better t h a n that avail able from resistance controls, a n d losses a r e low u n d e r all load conditions. A change in output voltage does not necessitate an interruption in current — there is n o changing of taps — output current is not restricted during ad- . justment — a single k n o b determines voltage, ad justable to a n y value from 0 to 1 7 % above line voltage — a calibrated scale insures high accuracy of setting. Most Variacs n o w have t h e new D u r a t r a k contact surface, the most important improvement in Var iacs since their original development — D u r a t r a k insures longer life, higher ratings per unit size a n d practically n o maintenance — Variacs with D u r a trak will withstand initial surges ten times the»F ratçd current a n d will operate at overloads for g y g a ^ · peiWds w i t h o u t faiiure.
Hetin, describing i n c o m p l è t e G - R line, sent o n request.
Variac
A listing of the more popular 50-60 cycle units of the Variac All "V" model Variacs contain the new Duratrak
M O T O R SPEED C O N T R O L
Type
for Operation of D-C Motors from A-C Lines
V-2
This electrical motor control is vastly superior to ordinary mechanical speed controls. A Variac with selenium rectifiers in the output makes for a most versatile and efficient instrument. There are no electron tubes insuring ruggedness and dependability. Other advantages are Good Regulation — High Starting Torque — Wide Speed Range — Low Cost — Compactness—Easy Installation, Maintenance and Operation. These Controls are available in six sizes ranging from Ms hp to IVi hp units. Prices $75 to $495.
V-5 7.5
II III
10
13.0
II III
V-20 V-20M
20
26.0
SO-A
40
V-5M V-SMT
18.50 20.50 25.00 33 00 c ΕΛ 35.50 40 00
V-10
V-10M V-IOMT
(Motors extra),
I IV
45.0
IV
V-SH V-5HM V-5HMT
2.6
I II III
V-IOH V-10HM VIO-HMT
5.2
V-20H V-20HM
50-B
®
-·;Amperes Price Rated Maximum Mounting: I I - $ 12.50 3-0
Variac
10.4 20
31.0
1 l
-
49.00 55.00 140.00 21.00 23.00 27.50
I 34 00 II 36.50 Ill 41.00 — *• I j 49.00 IV 55.00 ; w ~ - ^~rz~zz~ IV 140.00
Specifications at left are for Variac connections in which output voltage varies from zero to a maxim u m value equal to input line voltage. All models in t a b l e at left are shipped ready for over-voltage operation, providing a maximum output voltage of 17% above line voltage at r e d u c e d " M a x i m u m A m p e r e s . " Dials are calibrated from 0 to 1 7 % above line voltage. if Variacs with " 0 t o line volta g e " connections a n d dials so calibrated are desired, please specify in ordering. Variacs c a n b e used singly, ganged for higher power, or in polyphase connections. Variacs for use from 2 5 to 1 2 0 0 cycles are also available. sfc Mounting Information — Please order by TYPE NUMBER, not b y " M o u n t i n g " designation. I Uncased model IT Protective case a r o u n d windings III Protective case, terminal covline switch, a-c outlet er, a n d line cord IV Protective case, terminal cove I a n d BX outlet iiiimjjjytmi »»j»mpjpMf
" "fee sèf-iB*^. # Τ ^ * Ϊ Κ > ^ * * Κ 1 Ε ^ f . o b . Cambridge «rW.ConcorCMaSs-
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GENERAL RADIO Company
275 Massachusetts Avenue, Cambridge 39, Massachusetts, U.S.A. 8055 13th St, Si/wr Spring. Md..&tkSHtt*&t>N.,-i--&920 S. Michigan Aviiwf CftfiAOO '* ' 1000 Ν Seward Street i o s AHO«liS 3 ·
line
Circle «umber 45 A on Readers' Service Card, page 57 A
