Series BQX
BQX Series Explosion-proof VFD (Soft Start) Device
A flameproof cabinet built around a soft starter or frequency inverter, for starting and speed control of motors in classified areas. The VFD or soft starter, circuit breaker, contactor and instrumentation are housed inside the enclosure, with a full protection set and a digital display for frequency, speed and load — and the drive can be commanded from the plant DCS.
- Ex db eb IIB T4/T6 Gb
- Ex db eb IIC T4/T6 Gb
- Ex tb IIIC T80°C Db
- Soft starter or inverter inside
- 1.5 – 30 kW
- DCS signal control
Technical data
| Parameter | Value |
|---|---|
| Series | BQX |
| Ex marking | Ex db eb IIB T4/T6 Gb; Ex db eb IIC T4/T6 Gb; Ex tb IIIC T80°C Db |
| Protection | Ex db eb — flameproof (Ex d) combined with increased safety (Ex e) |
| Housing | Die-cast aluminium alloy, or welded steel plate with high-pressure electrostatic plastic spray, or welded stainless steel with exposed stainless steel fasteners |
| Built-in devices | Soft starter or inverter (ABB, Schneider and others), circuit breaker, AC contactor, ammeter, voltmeter and signal lamps |
| Protection functions | Overcurrent, short circuit, overvoltage, undervoltage, momentary power failure, phase loss and stall |
| Control and display | Digital display of frequency, rotation speed and load rate or current; manual frequency adjustment; speed-versus-time process curve setting |
| Plant integration | Controllable via DCS signal |
| Rated voltage | AC 220 / 380 / 460 / 690 V; DC 110 / 220 / 36 / 24 V |
| Rated power | 1.5 – 30 kW |
Features
- Recognised drive brands — the built-in soft starter or inverter is an established unit such as ABB or Schneider, selected to the duty.
- Complete starting assembly — circuit breaker, AC contactor, ammeter, voltmeter and signal lamps are housed in the same enclosure as the drive.
- Full protection set — overcurrent, short circuit, overvoltage, undervoltage, momentary power failure, phase loss and stall protection.
- Digital display — frequency, rotation speed and load rate or current shown at the cabinet.
- Manual frequency adjustment — the drive can be set locally, without external equipment.
- Speed-versus-time curve setting — the starting and running profile is configured to the process, rather than left at a fixed ramp.
- DCS control — the unit can be commanded from the plant control system as well as locally.
- Housing options — die-cast aluminium alloy, welded steel plate with high-pressure electrostatic plastic spray, or welded stainless steel with exposed stainless steel fasteners.
- Two gas groups, two temperature classes — IIB or IIC, T4 or T6, and an Ex tb IIIC T80°C Db variant for combustible dust areas.
- Rated power 1.5 to 30 kW — with AC 220 / 380 / 460 / 690 V and DC 110 / 220 / 36 / 24 V supplies.
Where the BQX series is used
- Starting and speed control of pumps, fans, compressors, mixers and agitators inside a classified area
- Drives where the starting current has to be limited rather than taken direct on line
- Duty changes that call for a controlled ramp instead of a fixed starting characteristic, using the speed-versus-time curve setting
- Skid and package units that are commanded from a plant DCS rather than operated only at the panel
- Plants that must keep the motor control close to the equipment instead of running cables out to a safe-area motor control centre
Need a different drive, power or interface?Send the motor rating and starting requirement, the zone and gas group, the supply voltage and the control interface (local, DCS or fieldbus), and we will confirm the drive, the enclosure size and the exact Ex marking.
For distribution and switching cabinets in the same range, see the BX series intelligent distribution box and the BXM(D) distribution box. Motor control cabinets are specified with the same enclosure and entry rules as other apparatus — see the electrical apparatus range.
