Explosion Proof VFD Panels
Variable Frequency Drives (VFDs) offer unmatched energy savings, process control, and motor protection but integrating them into Zone 1 or Zone 2 hazardous areas presents a significant engineering challenge. VFDs generate substantial heat, contain power electronics unsuitable for flameproof enclosure, and require ventilation. The solution is Ex p (purging and pressurisation) and Team Switchgear and Control LLC is a UAE specialist in designing, building, and testing Ex p certified VFD panels for Oil & Gas, Petrochemical, and Offshore applications.
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Ex p (pressurisation and purging) panels maintain a positive internal pressure using clean instrument air or inert gas, preventing the hazardous atmosphere from entering the enclosure. Before the panel can be energised, an automated purge cycle flushes the internal volume with a minimum of 5 air changes (Type X, Y, or Z purging per IEC 60079-2 / NFPA 496). A pressure monitoring controller continuously monitors internal pressure and de-energises the panel if pressure drops below the required setpoint ensuring the VFD is never live in an unpressurised state.
This approach allows standard commercial VFDs Siemens SINAMICS, ABB ACS series, Schneider Altivar, or Rockwell PowerFlex to be installed inside the pressurised enclosure without requiring the drive itself to carry an Ex certification, dramatically expanding the drive options available and reducing cost.
- Type X Purging reduces the classification inside the enclosure from Zone 1 to non-hazardous. Required for Div 1 / Zone 1 applications with ignition-capable internal components. Automatically de-energises on pressure loss.
- Type Y Purging reduces classification from Zone 1 to Zone 2. Used where internal components are incapable of causing ignition under normal operation.
- Type Z Purging reduces Zone 2 to non-hazardous. Most economical option, suitable for Zone 2 only installations.
Can you supply LCS with both local and remote control capability?
Yes. We regularly supply LCS units with an integral HOA (Hand/Off/Auto) selector switch that enables the operator to select between local manual control at the station and remote control from a DCS, PLC, or MCR. The HOA switch in the ‘Auto’ position passes control to the remote system; in ‘Hand’ position, the local pushbuttons are active. Feedback signals (running, tripped, valve position) can be provided via Ex i (intrinsic safety) 4-20mA loops or digital I/O.
What is your lead time for custom explosion proof LCS?
Standard 2–3 element LCS units (start/stop, E-stop) in GRP or aluminium Ex d enclosures are typically available within 3–6 weeks from approved drawings. More complex multi-function stations with custom operators, indicators, and instrument interfaces require 6–10 weeks. Rush delivery can be discussed depending on component availability.