GE Vernova MVAW 11/13/21 type intermediate relay

GE Vernova MVAW 11/13/21 type intermediate relay

In the fields of power systems and industrial automation, long-distance transmission of control signals always faces many challenges. Long control cables (also known as "long lead wires") not only introduce induced AC voltage interference, but also have problems such as voltage drop and signal attenuation, which may cause control equipment to malfunction or refuse to operate. To address these challenges, GE Vernova has launched the MVAW 11, MVAW 13, and MVAW 21 series intermediate relays. This classic electromagnetic auxiliary relay, with its unique design, ensures reliable and precise remote control of switchgear and related devices even in harsh electromagnetic environments and long-distance transmission conditions.

Product Overview: Designed for long-distance control

The core mission of MVAW series intermediary relays is to act as a robust 'middleman' between the control room (or protection screen) and the controlled switchgear (such as circuit breakers, contactors). It receives DC voltage signals from the control system and drives field devices through its high-capacity contacts. Its design has been optimized specifically for long lead wire applications:

Not sensitive to AC induced voltage: Long cables inevitably couple with AC induced voltage. The MVAW relay integrates a tubular slug in the coil assembly, giving it natural immunity to 50Hz AC voltage and preventing misoperation due to induced AC. For relays with 48/54V specifications, the typical AC suppression capability can reach 110V.

High pull in current: The relay has a pull in current of not less than 25mA, which allows it to be used in conjunction with a corrosion-resistant negative potential bias device. In applications that require the application of a DC negative potential to prevent cable corrosion, high pull in current ensures that the relay still has sufficient energy to reliably operate.

Sturdy attraction armature design: Adopting the classic attraction armature structure, the action is crisp and powerful, with high mechanical stability and long electrical life. Both standard contacts and "arc blowing contacts" with arc extinguishing function can meet strict load requirements.

Model selection and functional differences

The MVAW series offers three basic models based on the different contact reset methods and pole numbers:

Model Contact Type Characteristics and Applications

MVAW 11 self resetting contact (instantaneous) single pole relay, the contact acts when the coil is excited, and the contact automatically returns to the initial state after the coil loses power. Suitable for most remote control scenarios that do not require signal maintenance.

MVAW 13 manual reset contact (magnetic hold) single pole relay, the contact acts and mechanically holds when the coil is excited, even if the coil loses power, the contact state remains unchanged. It is necessary to manually operate the local reset button to return. Suitable for situations that require fault memory or do not allow automatic reset.

MVAW 21 self resetting contact (instantaneous) bipolar relay, providing two independent sets of self resetting contacts. Provides more control nodes under the same panel opening size, suitable for applications that require simultaneous control of multiple circuits.

Optional action indicator: All models can be equipped with a mechanical manual reset action indicator, which is used to indicate whether the relay has ever acted. Even after the auxiliary power supply disappears, the indicator can still maintain its state, providing important information for troubleshooting.

Deep analysis of technical characteristics

1. Principles and advantages of communication inhibition

The most prominent feature of MVAW relay is its AC suppression capability. By cleverly embedding a copper or aluminum "damping tube" (short-circuit ring/sleeve) in the electromagnetic system, when the alternating induced voltage generates alternating magnetic flux in the coil, the damping tube will induce a huge eddy current. The magnetic flux generated by the eddy current is opposite to the direction of the main magnetic flux, greatly weakening the influence of the alternating magnetic flux on the attraction of the armature. This makes the relay only respond to DC control signals and has a natural "filtering" ability for AC noise induced in long cables, without the need for additional external filters. According to technical data, for relays with 48/54V specifications, their maximum suppression capability for 50Hz AC can reach 110V.

2. Scope of work and control circuit resistance

The reliable operating range of a relay depends on the control voltage and the resistance of the lead wire circuit. Taking the 48/54V relay as an example:

When the resistance of the lead wire is 0 Ω, the operating voltage range is 37.5-60V dc.

When the resistance of the lead wire is 200 Ω (which is a typical long-distance control circuit resistance value), the operating voltage range is 44-60V dc.

The maximum lead wire loop resistance is 200 Ω, which provides a clear design boundary for remote control.

3. Pull in and release current

Pull in current: not less than 25mA. This relatively high current value ensures that even in the presence of large distributed capacitance and ground leakage resistance in the lead wire, sufficient ampere turns can still be established at both ends of the coil to drive the armature.

Release current: not less than 15mA. This ensures that the relay can be released cleanly and cleanly after the control signal is cut off, without sticking due to residual voltage.

4. Action time

Pull in time: At a rated voltage of 48V, when the resistance of the lead wire is 0 Ω, the typical pull in time is about 50ms (4-contact load); When the resistance of the lead wire increases to 200 Ω, the suction time is about 80ms. This delay characteristic needs to be considered when coordinating with the timing of the automation system.

Reset time: less than 35ms, ensuring quick response to the revocation of control instructions.

5. Contact capacity and load capacity

MVAW relays offer two types of contacts: standard contacts (for general control of AC/DC) and heavy-duty arcing contacts (specifically designed to enhance DC breaking capability).

Connection and continuous carrying:

Can continuously carry 5A current.

It can withstand a surge current of up to 30A in a short period of time (3 seconds), making it very suitable for connecting loads with high surge currents (such as relay coils and capacitor banks).

Breaking ability:

Communication: Standard contacts can disconnect 1250VA (maximum 5A/300V).

DC: Standard contacts can break 1250W (maximum 5A/300V) for resistive loads, but for inductive loads, the breaking capacity drops to 50W. This is determined by the difficulty of extinguishing DC arcs.

Heavy duty arcing contacts: When it is necessary to disconnect high DC voltage and current, heavy-duty contacts with magnetic arcing must be selected. The manual provides a specialized breaking capacity curve chart, indicating that under specific DC voltages (such as 48V, 110V, 220V), the blown arc contact can safely break DC currents ranging from several amperes to tens of amperes, greatly expanding the application range of relays.

6. Power consumption and insulation

Power consumption: At the rated voltage of 54V, the coil power consumption is 3.7W, which belongs to energy-saving design.

Insulation strength:

All terminals to housing: 2kV rms, 1 minute.

Between independent circuits: 2kV rms, 1 minute.

Between normally open contacts: 1kV rms, 1 minute.

Impulse withstand voltage: Complies with IEC 60255-5 and can withstand a peak impulse voltage of 5kV (1.2/50 µ s).

Compliant industrial standards and environmental adaptability

The MVAW series relays are designed strictly in accordance with international standards and are suitable for various harsh industrial environments.

1. Electromagnetic compatibility

High frequency interference: Complies with IEC 60255-22-1 Class III standard, can withstand interference between independent circuits and up to 2.5kV peak to ground, and can withstand up to 1.0kV peak between terminals of the same circuit (except for contacts).

EMC Directive: Compliant with 89/336/EEC, proven to comply with EN 50081-2 (Universal Emission Standard) and EN 50082-2 (Universal Immunity Standard) through the Technical Construction File (TCF) route.

2. Product safety

Low Voltage Directive: Compliant with 73/23/EEC, its safety is demonstrated by referencing general safety standards such as EN 61010-1 and EN 60950.

3. Environmental adaptability

temperature

Operation: -25 ° C to+55 ° C

Storage and transportation: -25 ° C to+70 ° C

Humidity: Can withstand a humid and hot environment of 56 days, 93% relative humidity, and 40 ° C as specified in IEC 60068-2-3.

Protection level: The shell complies with IEC 60529 IP50 and has dust-proof capability.

Vibration: Complies with IEC 60255-21-1 Class 1 response level and can withstand slight vibrations during operation.

Mechanical Structure and Installation

The MVAW relay adopts a modular plug-in structure (specific wiring needs to refer to the product manual), which is easy to maintain and replace.

Shell size:

MVAW 11 and MVAW 13 (single pole) use a Size 2 casing.

MVAW 21 (bipolar) adopts a Size 4 casing.

Installation method: Typically, embedded panel installation or backplate installation is used, with the wiring terminals located at the rear of the housing.

Ordering Information and Selection Guide

When ordering MVAW series relays, in order to ensure obtaining products that meet application requirements, the following information must be clearly stated:

Relay model: MVAW 11, MVAW 13, or MVAW 21.

Rated voltage: Select the correct coil voltage specification, and the optional range includes:

30/34V dc

48/54V dc

110/125V dc

220/250V dc

Contact type:

Standard AC/DC contacts (for general control)

Heavy load DC arc blowing contact (used in situations where high DC loads need to be disconnected, the capacity needs to be confirmed by referring to the curve diagram).

Optional operation indicator: Clarify whether a manual reset mechanical indicator is required.