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Simplifying Complexity. Delivering Safety.
Simplifying Complexity.
Delivering Safety.

Motor Pre-Start Ventilation Systems for Low Temperatures

IECEx & ATEX certified pre-start ventilation systems for large Ex e & Ex n electrical machines at low temperatures


  • Certification to -40°C
  • Pre-start ventilation flow capacity up to 14,000 Nl/min
  • Remote start options
  • Stainless steel enclosure construction

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  • Description
  • Specifications
  • Downloads
  • Certificates
  • 3D Models


Building on the range of pre-start ventilation systems for standard temperature, Expo have developed special systems for low temperature service as low as -40oC ambient.

The systems comprise the Control Unit (CU) and the Relief Valve (RLV). The Control Unit has two compartments – one is insulated and heated and contains the control logic system, while the other is unheated and contains the main air control components, which are rated for use at very low temperatures.  Key points within the CU are fitted with RTDs to provide temperature monitoring. The RLV measures air flow at the outlet and provides over-pressure protection for the machine.

If the purge air supply is below -40oC then Expo recommend the use of an in-line air heating system.




Air Inlet
Instrument quality air, 4-10 barg
Pre-start ventilation flow rate
User selectable:
3PV: 500, 1,000, 1,500 Nl/min.
5PV: 2, 3, 4, 5, 6,000 NI/min.
7PV: 7, 8, 10, 12, 14,000 Nl/min.
Temperature range
-40°C to +60°C
Pre-start ventilation timer
1-99 minutes
Timer power source
IS (Intrinsically Safe) Battery or Electro-Pneumatic Power Supply (EPPS)
Signal Inputs/Outputs
Inputs: Remote start (if option selected)
Outputs: Ventilation in progress; Ventilation complete.
Connection: Ex e junction box
Optional Ex i, Ex d junction boxes.

* Not all certifications may apply to all system variants. Check the specific Operating & Maintenance Manual for details.