Schneider Electric 33662 MX Shunt Release 200/250 V AC/DC

33662: MX shunt release, 200 to 250 V AC/DC

The 33662 is a Schneider Electric MX voltage release: an opening coil that trips a circuit breaker on command when its control voltage is applied. The datasheet describes it as an MX shunt release for ComPact NS630b to NS3200 fixed breakers and MasterPact NT and NW, rated 200/250 V DC and 200/250 V AC 50/60 Hz. Seven Star LLC supplies the 33662 in Oman and the GCC as an independent supplier based in Muscat.

An MX release is what turns a breaker into a remotely tripped device. A push button, a protection relay, an emergency-stop chain or a PLC output energises the coil, and the breaker opens without any overcurrent being present. It is an accessory, so the breaker, its frame and its trip unit are separate items.

Technical specifications of the 33662

How an MX opening coil works in a breaker circuit

An MX release contains a coil acting on the breaker’s tripping mechanism. When the coil is energised above its operating threshold, the mechanism releases and the contacts open. The datasheet gives this threshold as 0.7 to 1.1 x Un for opening, so the coil is expected to trip the breaker at any control voltage in that window, which for the 200 to 250 V rating corresponds to roughly 140 V to 275 V (calculated from the datasheet band).

Both AC (50/60 Hz) and DC supplies are covered by the same part, which simplifies stocking: one reference serves a plant with a 230 V AC control supply and one with a 220 V battery-backed DC supply. The supply holding power is 4.5 VA, a figure that matters for the sizing of control transformers or relay contacts feeding several coils in parallel.

Response time of the 33662 by breaker family

The datasheet distinguishes response time by the breaker the coil is mounted on: 50 ms ± 10 % on ComPact NS630b to 1600 and NS1600b to 3200, 55 ms ± 10 % on MasterPact NT and 70 ms ± 10 % on MasterPact NW. The coil is the same; the difference reflects the mechanism it acts on.

These numbers are about the time from applying the control voltage to the opening of the release, not the total clearing time of a fault. For a trip-on-fault scheme with an external relay, the relay operate time, the contact bounce and the breaker’s own opening time all add to it; the system study should use manufacturer data for the full chain.

Compatible breakers and related parts for the 33662

On the ComPact side, the datasheet lists the new-generation NS630b to 1600 and NS1600b to 3200 frames, and it marks the part as a spare for MasterPact NT and NW. In the breaker group that Seven Star LLC handles, the matching frames include the ComPact NS1600 breakers 33482, 33484, 33568 and 33570, the NS1250 breakers 33564 and 33566, and the NS630b and NS800 breakers 33546 and 33555.

Other accessories for the same frames, such as the OF auxiliary contact 33801, are separate part numbers; a complete trip-and-signal arrangement normally needs both a release coil and an auxiliary contact to tell the control system that the breaker has opened.

Installation notes for the 33662

The 33662 is an accessory for the breaker’s mechanism, so fitting it is a bench or switchboard job that needs the breaker de-energised and locked off. After fitting, connect the control wires to the terminals of the coil, check the polarity if the supply is DC and test it at the lowest and highest control voltage the plant can produce.

Because the coil is rated for an opening threshold of 0.7 to 1.1 x Un, a weak battery or a long, thin control cable can drop the voltage below the threshold under load. Measure the voltage at the coil while the breaker is being tripped, not just at the source, and test the circuit periodically as part of the protection maintenance plan.

Applications in Oman and the GCC

In Oman and the GCC the MX release is used on emergency-trip circuits in oil and gas facilities, on remote tripping from fire-and-gas systems, on load-shedding and generator-changeover schemes in power plants, and on tripping from transformer protection relays in utilities. In hot, dusty switchrooms, a periodic function test of every shunt release is cheap insurance: a coil that has never been energised since commissioning is the most common reason for a remote trip failing.

Selection checklist for the 33662

• Breaker frame and generation: ComPact NS630b to 1600, NS1600b to 3200, MasterPact NT or NW.
• Control voltage and type: AC 50/60 Hz or DC within 200 to 250 V.
• Number of releases: an MX opening coil is one of several possible release types, so state clearly that MX is required.
• Response-time need for the protection scheme (50, 55 or 70 ms depending on frame).
• Quantity and delivery location.

Information to send with an RFQ for the 33662

Please send the part number 33662, the quantity, the breaker model and serial or nameplate photo it will be fitted to, the control voltage available on site, and the delivery location in Oman or the GCC.

Documents and quotation

The official English datasheet for the 33662 is attached on this page. It lists the control voltage, operating threshold, response times and packaging data used above.

To request a quotation, send the part number 33662, the quantity and the delivery location. Seven Star LLC is an independent supplier in Muscat and quotes according to current availability.