Type VAGM 22

Instantaneous Voltage Relays

Type VAGM 22
Instantaneous Voltage Relays

VAGM 22 relay
withdrawn from case

Features General description Technical data

l Adjustable setting range. VAGM 22 is a standard attracted Voltage ratings and settings
armature relay with seven equal Relays are supplied suitable for
l Very high drop off/pick up ratio.
settings adjustable on a plug board. operation on 110 volts, 50 Hz
l Unaffected by normal variation in system and have the following
A dc coil is used with an internally
frequency of input voltage. standard setting ranges:
mounted bridge rectifier to obtain a
l Simple and robust construction. drop off/pick up ratio of the order of Over-voltage relay:
l Positive action without chatter. 90%. A resistance connected in 110 - 140% adjustable in seven
series with the coil is tapped suitably equal steps
and the taps are connected to the
Application Under-voltage relay:
plug board to obtain seven equal
Instantaneous over-voltage settings. A capacitor is used to serve 40 - 80% adjustable in seven equal
protection of generators, capacitors as a filter unit for the bridge rectifier steps
etc., definite time undervoltage and it also acts as a surge Resetting voltages
protection of ac motors, automatic suppressor for protecting the diodes
Over-voltage relay:
voltage changeover schemes and of the bridge rectifier against high
90% of setting voltage
other instantaneous and definite voltage transients.
time undervoltage and overvoltage Under-voltage relay:
The dc coil is fitted with a normally
applications requiring adjustable 110% of setting voltage
open light duty contact which is
settings.
arranged to energise an auxiliary Operating times
unit which provides the necessary
Over-voltage relay:
output contacts.
0.060 second at 110% voltage
Type VAGM 22 is a single pole relay setting
with its auxiliary unit.
Under-voltage relay:
0.025 second at zero voltage
These times are inclusive of the Contact ratings
operating time of the associated The contacts of the auxiliary unit of the relay are rated as follows:
auxiliary unit.
Type of Current Make & carry Make & carry Break
Burdens (VAG coil) contacts continuously for 3.0 sec
Over-voltage relay: Standard AC 1250VA with 7500VA with 1250VA with
Maximum burden at nominal maxima of 5A maxima of 30A maxima of
voltage is 0.9VA. and 660V and 660V 5A and 660V
Under-voltage relay: Standard DC 1250W with 7500W with 100W (resistive) or
Maximum burden at nominal maxima of 5A maxima of 30A 50W (inductive)
voltage (i.e. relay set at the lowest and 660V and 660V with maxima of
setting) is 2.5VA. 5A and 660V

Thermal rating Heavy duty DC 1250W with 7500W with 3¼ KW maximum

Over-voltage relay: magnetic maxima of 5A maxima of 30A
The VAG unit can withstand three blow-out and 660V and 660V
times the setting voltage on any
setting continuously. Dimensions and weights
Under-voltage relay: Maximum overall dimensions Approximate
The VAG unit can withstand two Relay Case size Height Width Depth* gross weight
times the pick-up (resetting) voltage mm mm mm Kg.
on any setting continuously.
VAGM 22 1D Vert. 233 170 203 5.5
Accuracy
* Add 76 mm for maximum length of terminal studs, alternatively, 29 mm
The over-voltage and under-voltage for terminal screws.
relays conform to error class index E
The approximate gross weight given above is inclusive of cartons,
5.0 as per BS 142-1966 and 5.0 as
mounting appendages and terminal details.
per IS 3231-1965.
Certified dimensional drawings of case outlines, panel cut-outs and
Operation indicator mounting details are available on request.
The relays can be fitted, if required, The relays comply fully with the requirements of IS 3231-1965 and are
with an operation indicator on the suitable for use in normal tropical environments.
auxiliary unit. The indicator is hand
reset by means of a push-rod Insulation Information required with
protruding through the relay case. The relay meets the requirements of order
On the under-voltage relay, a reverse IS 3231-1965/IEC-255-5 Series C-
operation indicator is fitted; i.e. it 2 kV for 1 minute. 1. Type of relay (undervoltage or
operates on drop-off or loss of overvoltage).
voltage. Case and finish
2. Nominal voltage rating. (If other
Relays are supplied in single pole,
Contacts than 110 volts ac suitable
metal drawout cases suitable for
interposing VTs will have to be
Upto three pairs of standard self- flush or projection mounting and
used.)
reset contacts can be provided on are finished eggshell black and
the auxiliary unit of the relay in any tropicalised. The drawout feature 3. Number and type (standard or
combination of ‘Make’ and ‘Break’. considerably simplifies maintenance blow out magnet) of ‘Make’ and
The auxiliary unit is always energised and permits testing to be carried out ‘Break’ contacts required.
by a normally open, light duty easily and quickly. A cradle 4. Whether operation indicator
contact of the VAG unit in case of mounted isolating switch is provided required. If so whether any flag
under-voltage relay. The auxiliary which automatically isolates the trip inscription is required.
unit can be fitted with blow-out circuit when the cradle assembly is
magnet contacts also, if required, for withdrawn from the case for 5. Voltage rating of the auxiliary
breaking heavy or highly inductive maintenance. This prevents any unit. (*)
dc loads. inadvertent tripping of the circuit 6. Type of mounting--flush or
breaker. The case can also be fitted projection.
The normal position, regarding the
with switches to maintain the under-
contacts, is the de-energised (*) It is preferable to have a dc or
voltage trip circuits on withdrawal of
position. separate ac auxiliary voltage
the relay unit from the case. A filter
breather is fitted to equalise supply for the auxiliary unit.
pressure inside and outside the case
without admitting dust.
 ALSTOM Limited Pallavaram Works: 19/1, GST Road, Pallavaram, Chennai-600 043. India.
Tel: 91-044-2368621 Fax: 91-044-2367276 Email: plw.applications@alstom.sprintrpg.eml.vsnl.net.in.
© 1998 ALSTOM Limited

Our policy is one of continuous development. Accordingly the design of our products may change at any time. Whilst every effort is made to produce up to date literature, this brochure should
only be regarded as a guide and is intended for information purposes only. Its contents do not constitute an offer for sale or advice on the application of any product referred to in it.
ALSTOM Limited cannot be held responsible for any reliance on any decision taken on its contents without specific advice

PR:066:0799:A Printed in India.