Chinese Supplier OEM WCQ2G-100 3P Dual Power Automatic Transfer Switch

This is the three-pole variant of Westhomes' WCQ2G-100 compact ATS, rated up to 100A frame size, used to switch a three-phase load between mains and a standby generator. As a Chinese supplier offering OEM, Westhomes can produce the unit with your own brand logo, silk-screen markings, packaging, and even custom controller parameters for distributors and EPC contractors.

"3P" means three poles — it switches the three phase conductors (L1, L2, L3) of a three-phase supply but keeps the neutral continuous. It is used when the neutral is shared and earthed on the supply side (e.g., two utility feeds or a generator whose neutral is not separately bonded). If your standby generator has its own neutral-earth bond, you should choose the 4P version so the neutral is also switched.

It suits three-phase 380/400V loads such as small machine tools, compressors, water pumps, elevators, commercial refrigeration racks, office HVAC, and small distribution boards in shops, factories, and telecom shelters. The frame current of 100A means it covers common three-phase circuits from the smallest ratings up to 100A; larger loads need the next frame size.

The controller continuously samples voltage, frequency, and phase sequence on both sources. If mains voltage collapses, drops to phase-loss, or drifts outside the accepted frequency band, the ATS waits out the set delay, starts the generator, verifies the generator output is within limits, and only then breaks the mains and makes the generator. Interlock hardware prevents both sources from being closed simultaneously, eliminating back-feeding.

The contact swing between sources is a fraction of a second on this PC-class ATS. End-to-end outage time — from mains loss to load restoration — is dominated by the generator start-up delay, typically 5–15 seconds depending on how you set the start and re-transfer timers. Adjustable delays let you ride through brief utility sags so the generator is not exercised for every flicker.

Source 1 (mains) and Source 2 (generator) feed the two input terminals, and the downstream distribution board connects to the output terminals, with all three phases on each side matched in rotation. The neutral is common and not switched on the 3P version. The control circuit uses the ATS's auxiliary contacts to start the generator; earth bonding and conductor sizing must follow local electrical code.

Yes. In AUTO mode it runs unattended; in MANUAL mode the operator can select source via the front pushbuttons, and a manual cranking handle allows mechanical operation even with power off. This dual mode is important for commissioning, routine testing, and emergency service when the controller is being worked on.

The WCQ2G-100 3P is built and tested to IEC 60947-6-1 (transfer switching equipment for voltages up to 1000 V AC), and is normally CE-marked. OEM orders can be accompanied by type-test reports, IP-rated enclosure data, and factory inspection certificates to support local market approvals such as CB, SASO, or INMETRO where required.

Typical OEM options include customer logo and nameplate printing, choice of controller language, adjustable time-delay ranges, colour or enclosure variant, packaging and user manual translation, and private-labelled cartons. MOQ, lead time, and sample policy should be agreed in writing before production starts, along with the exact technical datasheet.

A manual 3P changeover switch requires an operator to switch sources by hand and cannot start a generator, so any outage extends until someone arrives. The WCQ2G-100 3P ATS performs the whole sequence automatically — sensing, generator start, stable-source verification, transfer, re-transfer, and generator shutdown — and logs the events. It costs more but is essential for unattended sites and critical loads.