Description

ALSTOM DEFINITE TIME DELAY RELAY VTT11ZG8179BCH

VTT11ZG8179BCH Definite Time Delay Specification

• Type: Electro Mechanical Relay
• Protection Type: Definite Time Delay Relay
• GBVTT11ZG8179BCH

STATIC DEF TIME DELAY RELAY WITH DELAY O

Technical Specifications
Model No : VTT11ZG8179BCH
VTT11
APPLICATION – PICK UP
AUX. CURRENT OR VOLTAGE – 24 – 30V DC
CASE SIZE – 1/2N H 12T
CONTACTS (S/R OR H/R) – 2 N/O 2 N/C S/R
FLAG – YES
MOUNTING – FLUSH
TIME DELAY P/U OR D/O – 0.5 – 5 SECS.
External Resistor
Name Plate RZF9066-601
Outline Diagram MFM017
Wiring Diagram MZDZ601-01-2

VTT is a static time delay relay which is particularly suitable for applications requiring large number of operations and consistent accuracy with little or no maintenance over long periods. It is also commonly used in industrial processes.

Check synchronising relays are used to prevent interconnection of badly synchronised supplies. Type SKD relays are generally used in auto reclosing sequence of interconnectors along with the auto reclosing relay. Type SKE relays are used to safeguard manual synchronising of generators. The check synchronising relay contacts are normally connected in series with the circuit breaker closing circuit and ensures that the differences in phase, voltage and frequency are within pre-selected limits before switching in an incoming alternator or interconnecting two sections of a power system.

Features
• Consistent accuracy
• Reliability
• Low burden
• Reduced maintenance
• Immunity to transients and surges; withstands 5 kv impulse voltage test
• Relays with heavy-duty magnetic blow-out contacts also available

Type VTT 11 units have a delayed pick-up, i.e., timing is started by closing an initiating contact and the output relay is energised at the end of the set time. The unit resets when the initiating contact is reopened.
Type VTT 12 units have a delayed drop-off, i.e., the output relay is normally energised. Timing is started by opening an initiating contact and the output relay is de-energised at the end of the set time. The unit resets when the initiating contact is reclosed.

Type VTT 12 units have a delayed drop-off, i.e., the output relay is normally energised. Timing is started by opening an initiating contact and the output relay is de-energised at the end of the set time. The unit resets when the initiating contact is reclosed.

Technical data
Voltage ratings

DC supply
30, 48, 110 or 220V. Satisfactory operation is maintained between 70% and 130% of rated voltage.
Units for use on 110 or 220V are supplied with a suitable external resistor.

AC supply
110, 240 or 415V at 50 Hz. Relays suitable for operation from ac supply have a built-in power pack. Satisfactory operation is maintained between 80% and 115% of rated voltage.

Timing ranges
Models with the following setting ranges (in seconds) – continuously adjustable – are available:
0.05 – 0.5
0.10 – 1.0
0.50 – 5.0
1.00 – 10.0
2.50 – 25.0

Accuracy
Within ±5% of setting or ±10 milliseconds whichever is greater, at nominal voltage and at an ambient temperature within the range of 10ºC and 30ºC.

Within ±5% of setting or ±25 milliseconds whichever is greater for supply voltage variation for ±30%. Operating temperature range -5ºC to +50ºC.

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