Reversing starter cabinets
- Reversing: separate forward / reverse contactors, mechanical linkage + electrical normally-closed dual interlock
- For frequent jogging, contactors are upsized to AC-4 utilization category — service life is not compromised
- Interfaces: upper / lower limit, brake control, jog (inch) button — reserved to drawing
- Protection: circuit breaker + thermal overload relay or motor protection relay, against stall and phase loss
- Components: Schneider / ABB / Siemens / Chint; brand can be specified, or customer-supplied components shipped to our plant
Specifications
The table below covers 80% of factory distribution room cases. Anything outside it we can still build — those are engineered items, quoted separately, with an indicative price the same day.
| Type | Wall-mounted (≤11 kW) / floor-standing, single door |
|---|---|
| Standard sizes (W×D×H) | 500×300×700 (wall-mounted) / 800×600×1600 (floor-standing) mm, custom build available |
| Enclosure construction | 1.5–2.0 mm cold-rolled carbon steel, bent and welded, electrostatic powder coated |
| IP rating | IP54 standard / IP65 optional |
| Operator panel | Forward / Reverse / Stop buttons + jog (inch) button + direction indicator |
| Cable entry | Bottom cable entry; remote pushbutton box (with emergency stop) supplied as needed |
| Rated operating voltage | AC 380V / 400V, 50 Hz; control circuit AC 220V or DC 24V |
|---|---|
| Applicable Power | 0.75–75 kW three-phase induction motors |
| Reversing configuration | KM-FWD + KM-REV contactors, reversing busbars factory pre-fabricated |
| Interlock | Mechanical linkage + electrical normally-closed contact dual interlock |
| Utilization category | Standard AC-3 duty; for frequent jogging or shock loads, size up per AC-4 |
| Protection configuration | Circuit breaker plus thermal overload relay or motor protection device; locked-rotor and phase-loss protection |
| Provision for future interface | Upper and lower limit switches, ultimate limit switch, brake contactor, jog, remote control push-button box |
| Component brands | Schneider / ABB / Siemens / Chint; customer-supplied components accepted for factory installation |
| Hoist / lifting type | Limit switches + brake + jog; overspeed and slack-rope signals wired in as required |
|---|---|
| Crane / electric hoist type | Remote control push-button box (with emergency stop); multiple mechanisms in separate cabinets |
| Gate / flap type | Open / close position limit switches + torque protection (actuator signals) |
| Trolley traverse type | Limit switches at both ends + timed reversal; unattended back-and-forth operation |
| Interfaced with PLC | Direction controlled by PLC dry contacts; manual priority retained inside the cabinet |
| Assembly standard | GB/T 7251.1 / IEC 61439-1 |
|---|---|
| Interlock verification | Verify mechanical linkage and electrical interlock operation unit by unit |
| Routine tests (every unit) | Insulation resistance, power-frequency withstand voltage, forward → stop → reverse power cycle × 3 |
| Temperature rise | Contactor and terminal connections ≤70 K |
| Documents with shipment | Schematic diagram, terminal list, limit switch / brake interface description, BOM, test report |
Five steps to specify your run
A configuration summary is generated as you go. It travels with your inquiry, saving a round of confirmation.
Build details
Systems have been in service for decades, and the failure points are always the same few: poor busbar contact, water ingress at the door seal, high temperature rise in the correction cabinet, and mis-phased outgoing feeders. The six hard rules below are written for exactly these points — every cabinet can be traced to them.
Interlocking is the bottom line
Mechanical linkage plus electrical normally-closed contacts provide dual interlocking. If either contactor sticks in the closed position, the other cannot close. This is the lifeline of a reversing cabinet.
For jogging duty, select for jogging
Under frequent jogging, contactor contact erosion is normal. Size up one to two frames per AC-4 duty class, and both service life and reliability hold up.
Limit switches and brakes terminate at the terminal block
Limit switch, brake, and jog signals are all wired to the terminal block and tagged. On site, only field devices are connected — no secondary wiring is touched inside the cabinet.
Forward/reverse cycling, one unit at a time
At the factory, each unit runs 3 forward → stop → reverse cycles, with interlocking and indicator light sequencing verified in sync.
Factory pre-fabricated, no field modification
The reversing section busbar is pre-fabricated in the workshop and phase-marked. Phase sequence is never changed on site.
Emergency stop at a higher level
The emergency stop on the remote control box is wired in series with the control power circuit. Pressing it during operation in either direction immediately disconnects and latches out.
Photos & enclosure construction
Below are photos taken in our own shop — from the complete unit down to the internal busbars and secondary wiring. Every build detail can be checked item by item.
Image key: 01–05 are shop photos (the numbers match the shot list). The line drawing shows the front elevation of the enclosure; dimensions match the specification table above.
Where these cabinets go
These are the routine applications — we can talk scheme and configuration directly. For the industry view, see the industry pages.
Winches and hoisting equipment
Limit switches + brakes + jog/inch control for precise positioning.
Overhead cranes and electric hoists
Separate branch control for bridge / trolley / hoist motions, operated from a remote control box.
Flap gates and coal plows
Open-position / close-position limit switch stop, with torque protection against jamming.
Reciprocating carts and feeders
Automatic reversing at both end limits, with optional delayed soft reversing.
Mixing with forward/reverse discharge
For reverse discharge duty, contactors are selected per jogging class.
Pair with VFD reversing
For reciprocating equipment requiring speed control, switch to a VFD solution; direction is reversed by contactor or by VFD output phase reversal.
Commercial terms
Specification dated September 2026; quotations follow this.
| Drawings & design | Free |
| MOQ | 1 unit (5 or more recommended for production) |
| Production lead time | 15-25 days after drawing approval |
| on-time delivery | 98% |
| Warranty | 12 months |
| Loading port | Ningbo / Shanghai, China |
| Component brands | Schneider / ABB / Siemens / Chint |
| Factory visit & dispatch confirmation | Factory visits welcome; finished-cabinet photos and video before dispatch |
| Capacity | 5,800+ units / year |
Documents for your engineering team
Selection manual, outline dimensions and RFQ checklist — for the customer's electrical engineer. All three documents are being organized by product line; download links go live once complete.
Six questions procurement and electrical engineers ask most
Why must forward/reverse have dual interlocking?
If both contactors close at the same time, supply lines L1/L3 short directly, burning contactors or even busbars within tens of milliseconds. The mechanical linkage prevents sticking and welding; the electrical normally-closed contacts prevent false operation. Each guards against a different failure mode — installing only one is a hazard.
Will frequent jogging burn out contactors?
Standard AC-3 contactors do lose service life rapidly under frequent jogging. We size up per AC-4 duty class and leave replacement margin. For especially severe duty (more than ten operations per minute), we recommend a VFD solution directly — contactless reversing does not have this problem.
Do you supply the limit switches?
Wiring and settings are pre-configured inside the cabinet. Limit switch bodies can be supplied with the cabinet (common travel / pendulum types) or provided by the customer. Models and contact configurations are clearly marked on the wiring diagram.
How is the brake controlled?
The brake coil is powered by a dedicated contactor interlocked with the motor contactor: when the motor is energized the brake releases, and when power is lost the brake engages. On lifting equipment, the brake circuit is protected separately and brakes on power loss.
Can it be fitted with wireless remote control?
Yes — we can provide a prewired interface: the wireless receiver's dry contacts are wired into the control circuit; the transmitter is supplied by the customer or sourced on their behalf. This is a common setup for overhead crane remote control, and it is shown on the wiring diagram.
How is forward/reverse switching handled above 75 kW?
For high-power phase reversal we recommend a soft starter or VFD solution (thyristor / IGBT contactless reversing), or a contactor reversing setup combined with soft-start current limiting. Send us the load characteristics and we will provide a comparison of options based on your operating conditions.
Other cabinet types in the same main circuit
Related products use color-block placeholders for now (product photos not yet complete; they will be replaced together). Internal links will be filled in once live URLs are confirmed.
For reciprocating equipment controls, let's discuss the operating conditions before specifying the cabinet
Send us the equipment type (winch / overhead crane / gate) along with your limit switch and brake requirements, and we will provide a reversing solution free of charge · quotation within 24 hours. Direct from the source factory, MOQ 1 unit, 15–25 day lead time, 1-year warranty.
ISO 9001:2015 · CE(LVD+EMC) · CQC · IP65
When you write, include: single-line diagram or primary scheme, switch room layout, load list, and component brand requirements. You do not need complete drawings — capacity and cabinet type are enough to start.