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.