UCS, Topp, Windowmaster, Built for the Most Demanding Applications
Product Overview
Rack actuators use a rack and pinion gear mechanism to deliver consistent force throughout the stroke with near-silent operation: well suited to long stroke applications, high-duty-cycle systems, and synchronised multi-point opening for large domes and rooflights. Vent Trade stocks rack actuators from UCS, Mingardi, and Topp in single, dual, double, and synchronised variants, covering strokes from 180mm to over 1000mm in 24V DC and 230V AC.
Electric rack and pinion actuator with 1000N push-pull force. 180–1000mm stroke in 110–240V AC or 24V DC RWA. For heavy windows and rooflights. Trade supply.
Versatile rack actuator for windows, rooflights, domes and louvres. 10mm and 12mm rack with 180-1000mm stroke. 230V AC and 24V DC.
Auxiliary rack actuator for synchronised dual-point opening. Pairs with primary UCS Rack via S1 Connecting Bar Kit. 180-1000mm stroke in 230V and 24V.
Main and auxiliary rack actuator kit with 12mm connecting rods. Dual-point actuation for larger windows, domes and louvres. 180-1000mm stroke in 230V and 24V.
Main and slave rack actuator kit with synchronised dual-point opening. 12mm connecting rods for larger windows and domes. 180-1000mm stroke in 230V and 24V.
Rack actuator with 500N thrust in three stroke lengths: 320, 500 and 750mm. For top-hung and bottom-hung windows, domes and skylights. 230V and 24V.
Synchronised T-Rack actuator for individual or group operation. Multiple stroke lengths for larger windows, domes and vents. 24V DC.
T-Rack actuator for rooflights, domes and large windows. 350-1000mm stroke in 230V AC and 24V DC. Speed sync available.
Rack actuators from UCS, Mingardi, and Topp: near-silent rack and pinion drive with consistent force throughout the stroke. Single, dual, and synchronised variants from 180mm to 1000mm+ in 24V DC and 230V AC. For chain and linear alternatives, see the full window actuators range.
For rack actuator selection guidance, call our technical team on 01202 725 689.
A rack actuator is an electric motor-driven window opening device that uses a rack and pinion gear mechanism to convert rotary motion into linear push-pull force. The motor turns a pinion gear which drives a toothed rack in and out of the actuator housing, providing smooth and consistent force throughout the entire stroke length.
Rack actuators are distinguished from chain and linear actuators by their near-silent operation, consistent force delivery at any point in the stroke, and suitability for long-stroke applications. They are widely used in smoke ventilation and natural ventilation systems across the UK, particularly for large commercial rooflights, domes, skylights, and facade windows.
Leading manufacturers including UCS, Topp, and Mingardi produce rack actuators in stroke lengths from 180mm to over 1000mm, available in 24V DC and 230V AC configurations to suit different control system requirements.
Selecting the correct rack actuator requires evaluating stroke length, force output, voltage, and whether single-point or multi-point actuation is needed. Stroke length must match the opening distance specified in the fire strategy or ventilation design: rack actuators are particularly advantageous for strokes above 400mm where consistent force delivery matters.
Force output must exceed the combined opening resistance of the window sash, including weight, friction, and wind loading, with a 20 to 30 percent safety margin. Voltage selection follows the same principles as other actuator types: 24V DC for smoke ventilation, either 24V or 230V for natural ventilation.
For larger windows, domes, and rooflights, consider dual-rack or synchronised systems such as the UCS Rack Dual or Synchro T-Rack, which provide coordinated two-point opening to prevent racking or binding of the sash. Always confirm the rack size (typically 10mm or 12mm) is compatible with the required bracket arrangement.
Rack actuators used in UK smoke ventilation systems must be installed as part of a system complying with BS EN 12101, the suite of European standards covering smoke and heat control. The complete smoke vent assembly (actuator, window or rooflight, and frame) must be tested and certified to BS EN 12101-2 as a natural smoke and heat exhaust ventilator.
Some rack actuators carry specific EN 12101-2 certification on their 24V DC variants (for example, the Mingardi DRIVE EVO2) providing evidence that the actuator has been tested as part of a certified vent assembly under fire conditions. The smoke control panel must comply with BS EN 12101-10, and the overall installation must satisfy Approved Document B of the Building Regulations.
For natural ventilation applications without a smoke control function, compliance with BS EN 12101 is not required but actuators should still meet relevant electrical safety standards.
Rack actuators are installed in applications requiring long stroke, high duty cycle, silent operation, or synchronised multi-point opening. Common installations include large commercial rooflights and domes in shopping centres, atria, and public buildings where opening distances exceed 400mm.
They are widely used on skylights in schools, hospitals, and office buildings where silent operation is important in occupied spaces. Rack actuators are also specified for facade windows in architectural projects where the smooth, quiet operation of the rack and pinion mechanism is preferred over the clicking sound of a chain drive.
Synchronised dual-rack systems are used on wide rooflights and domes where two-point actuation is required to prevent sash binding. In smoke ventilation systems, rack actuators are installed on AOV rooflights and large stairwell windows where the required free area demands a long actuator stroke and reliable force delivery.
Rack actuators require regular inspection and functional testing to ensure reliable operation over their service life. For smoke ventilation systems, BS 7346-8 recommends weekly visual inspections and monthly functional tests including full open and close cycling.
The toothed rack should be inspected for wear, contamination, or mechanical damage, and the actuator housing checked for water ingress: particularly on roof-mounted or exposed installations. Mounting brackets and connecting bars on dual-rack systems should be checked for tightness and correct alignment. Modern rack actuators are generally sealed units that do not require routine lubrication, but the manufacturer’s maintenance schedule should be followed.
For life-safety systems, a comprehensive annual service by a competent engineer is recommended, covering force output testing, stroke verification, electrical connection integrity, and synchronisation checks on multi-actuator installations. Replace any actuator showing signs of reduced performance, excessive play in the rack mechanism, or intermittent operation.