TYPE TSD-1000 WELDING TRANSFORMER WITH REMOTE CONTROL OF WELDING CURRENT

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00809A000600290921-7
• Release Decision: RIPPUB
• Original Classification: C
• Document Page Count: 4
• Document Creation Date: December 22, 2016
• Document Release Date: September 29, 2011
• Sequence Number: 921
• Publication Date: April 3, 1950
• Content Type: REPORT

Sanitized Copy Approved for Release 2011/09/29: CIA-RDP80-00809A000600290921-7
COUNTRY
SUBJECT
HOW
PUBLISHED
WHERE
PUBLISHED
DATE
PUBLISHED
LANGUAGE
CLASSIFICATION CONFIDF,,,jA
CENTRAL iNIELLIGENCE"AGER(3WLI 11, R.EPOR~
INFORMATION FROM
FOREIGN DOCUMENTS OR RADIO BROADCASTS CD NO.
Scientific - Electrical equipment
Monthly periodical
Moscow
May 1949.
THIN DOCONINT CONTAINS INIOINATION A/ICCTINI TAN NATIONAL 017/NI.
01 TNt VNITNO ITATIN WITHIN TN. N.1-INI III NIIIONANI ACT IO
V. f. C.. -1 NO M.. ..K.... 11. ON IN.
01 ITN CONT-Nn IN ANTT -- TO O AN %I-TNOIICID ..ANON 11 1.0.
NI.ITND T LAW. IVNYDOC"O- OI TNIt IOAN II tAONIfITIO.
DATE OF
INFORMATION 1949
DATE DIST. 3 Apr 1950
NO. OF PAGES 4
SUPPLEMENT TO
REPORT NO.
THIS IS UNEVALUATED INFORMATION
Vestnik Elektronmvshle nos t No 5, 1949,
TYPE TSD-1000 WELDING TRANSFORMER
WITH REMOTE CONTROL OF WELDING CURRENT
Engr S. M. Tas'ba
"Elektrik" Plant
LA diges]
The method of high-speed welding under a layer of flux is being more and
more widely used in the most diverse branches of industry. Due to the fact
that it is possible to use very large currents, this method ensures high pro-
ductivity in welding operations.
To feed the are in high-speed automatic welding installations, a heavy-
duty welding transformer is required as well as a regulator, permitting the
regulation of welding current directly from the control box of the automatic
apparatus. With this in view, the "Elektrik" Plant, in 1948, designed and
started series production of welding transformers with remote control for a
nominal welding current of 1,000 amperes.
The ordinary welding transformers made by the "Elektrik" Plant for manual
arc welding (Types STE-24 and STE-34 for 350 and 500 amperes) are made in two
sections. In contrast to this, the Type TSD-1000 transformer is made in one
section. The basic part (transformer) and the device which regulates the
welding current (reactor) are made on a common magnetic circuit according to
a scheme suggested by Academician V. P. Nikitin (first proposed in 1925,
patent No 3140).
The principle of this scheme is that the transformer and reactor portions
have a common yoke in which the magnetic fluxes are in opposition due to the
orientation of the windings. As a result of this, the dimensions of the yoke
not only need not be increased but can even be reduced as the resultant flux
under load will be considerably less in the yoke than in the remaining portions
of the magnetic circuit. However, in view of the fact that, when the trans-
former is on no-load, there will be no magnetic flux in the yoke from the
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reactor, it should be designed to take all the magnetic flux which passes
through it under no-load conditions. This type of magnetic circuit makes
it possible to reduce the expenditure of transformer steel, the weight and
the dimensions of the transformer, and to improve operational qualities by
decreasing the losses in the magnetic circuit.
Construction of the Transformer
The transformer consists of the following basic members: (1) the
magnetic circuit (core), (2) the transformer winding (primary and secondary),
(3) the reactor winding, (4) the mechanism for lifting and lowering the
movable portion of the reactor, (5) the interlocking and current indicating
mechanism, and (6) the stand in which the above basic elements are mounted.
Magnetic Circuit
The magnetic system consists of two basic parts, the lower fixed part
(on which the primary and secondary transformers are mounted underneath
and the reactor windings on top), and the upper movably
fixed and movable sections of the magnetic circuit consist cofVsheetsLofthe
transformer steel, mark E4A, 0.5 mU.lireter thick.
The movable reactor block slides along guide bars in such a way that a
gap in the core of the reactor can be varied, thereby regulating the inductive
reactance of the secondary circuit of the transfor
characteristic and a variation of the welding current inlthe requiredalimits.~g
'ransformer Windings
The primary and secondary transformer windings are not connected with
each other electrically. The primary winding is designed to be connected to
a single-phase 220 or 380-volt supply, but transformers are also made for
500 volts on special order. The secondary winding is made of uninsulated
copper wire.
The windings are in the form of two cylindrical coils, each of which
consists of two layers of primary winding and one layer of secondary winding.
Wooden separators are placed between the layers, thus forming air passages
and increasing the cooling surface. The secondary windings of both coils
are connected in parallel. The primary windings are connected in series
for 380 volts and in parallel for 220 volts. In this way, a secondary
no-load voltage of 65 volts is assured in both cases. Due to the fact that
the operation of heavy-duty automatic apparatus frequently causes a consider-
able voltage drop in the supply current, which in turn drops the secondary
voltage, provision is made for sectioning the primary winding by tapping the
corresponding turns and leading them out to a terminal board. When this step
arrangement is used, the secondary voltage on no-load will be 75 volts for
normal supply voltages.
The reactor winding consists of two coils made of bare copper bus bars
connected in series and insulated with asbestos inserts.
Mechanism for Raising and Lowering the Movable Block of the Reactor
As was pointed out above, the regulation of the welding current is
accomplished by altering the air gap in the middle part of the reactor core.
A three-phase electric motor (0.25 kilowatts, 1,420 rpm,) is used to drive the
mechanism which varies the reactor gap. Lifting and lowering the movable
block is accomplished through this mechanism (belt-driven) by reversing the
electric motor which is controlled by means of two magnetic starters, one for
each direction of rotation. An interlock is provided to avoid the possibility
of short circuits in case both buttons were pushed simultaneously.
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CONFIDENTIAL
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Interlocking and Current Indicating Mechanisms
Special cam mechanisms switch off the electric motor automatically
when the moving block reaches one of the extreme positions. The distance
between the extreme positions of the ma-netic circuit is about 80 milli-
meters. The shaft of the interlocking mechanism makes one incomplete turn
through the whole range of regulation of the welding current.
Corresponding positions of the cams on the shafts are fixed by means
of set screws. Each position of the camshaft of this mechanism corresponds
to a definite position of the movable reactor block and consequently, to a
definite value of welding current. This makes it possible to use the
mechanism to indicate current by means of a graduated disk mounted on the
free end of the shaft.
The welding current depends not only on the gap in the magnetic circuit
of the reactor, but also on the voltage at the terminals of the secondary
transformer winding and on the load resistance. Therefore:, strictly speaking,
.the graduated readings are correct only when nominal voltage is applied to
the terminals of the transformer with an ohmic load resistance in the second-
ary circuit corresponding to a voltage drop of 35 volts, which is considered
to be an average value for automatic arc welding under a layer of flux.
Accurate regulation of welding current can be done from the ammeter
mounted directly on the control panel of the automatic apparatus.
The transformer and all the mechanisms are mounted on a rigid welded
frame in an enclosed stand with double doors providing access to the interior.
The whole unit rests on a base with four wheels which enable the transformer
to be moved as required under operational conditions.
The main terminal boards are located inside the stand, or the lower side.
One of them is designed to connect the terminals of the secondary welding
circuit and the other, for connecting to the line. In addition to these
boards, there is another terminal board mounted inside. Its left three ter-
minals are for connecting up the three-phase line to the electric motor; the
right three terminals connected the two starting buttons for the remote con-
trol of welding current.
On the front panel of the stand there is a window revealing the current
indicating mechanism. Alongside this window there are two starting buttons
for welding-current control. Thus, in addition to remote control of welding
current, it is possible to regulate it directly at the transformer from the
current indicating scale. This is necessary when operating automatic machines
since remote control is carried out on the basis of an ammeter with the arc
already struck. Preliminary setting of the current must be done from the
indicator.
Technical Data
As noted previously, the transformer is built for a 220 or 380-volt
50-cycle single-phase power supply and is designed to operate on repeated short-
time duty alternated with intervals of rest. For a nominal welding current of
1,000 amperes, the switching duration factor is taken as 0.55. For currents
less than 1,000 amperes, the factor can be increased, while with currents above
1,000 amperes, it should be correspondingly reduced.
VD, L4
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The control of welding current is accomplished smoothly in the range
from 400 to 1,200 amperes. The upper limit can be attained with a secondary
voltage of 75 volts. The duration factor at this limit should not exceed
40 percent. The primary transformer current is approximately 310 amperes
at 220 volts and 180 amperes at 380 volts. The efficiency of the trans-
former is about 85 percent, while the power factor is approximately 0.5.
Sanitized Copy Approved for Release 2011/09/29: CIA-RDP80-00809A000600290921-7