Actuator motor for car power windows: the 12 V worm-gear DC drive, its Hall position signal and the anti-pinch limits it has to meet
Car window-lift and closure drives · the 12 V brushed motor with a self-locking worm stage, Hall pulses for position, and the FMVSS 118 limits its controller must stop within
A car window-lift actuator motor is a small 12 V brushed DC motor with a worm on its shaft driving a plastic worm wheel, packed in one housing with a connector and, depending on the variant, Hall sensors or a control board. The worm stage gives the reduction and holds the glass when the power is off; the Hall pulses tell the door controller where the glass is and how fast it moves. Because a window that closes by itself falls under safety rules written to prevent death or injury from accidental operation, the motor and its controller are bought against a force limit as well as a torque figure.
Brushed DC worm-gear drives for power-operated windows, sunroofs and partitions in passenger cars and light vehicles, with their Hall sensors or integrated electronics, and the anti-pinch requirements that shape them. Industrial AC and DC servo motors are covered on the Servo motor page; servo press modules on the Servo motor actuator for press-fitting page; servo motor and drive sets on the Servo motor and drive set page; integrated servo or stepper motors with built-in drive on the Integrated servo or stepper motor page; and BLDC drivers on the Motor driver for brushless DC motors page. Industrial worm and helical gear motors are covered on the Gear motor drive assembly page. Electric park brake, tailgate, mirror-fold and HVAC damper motors are outside this page.
CNFX editorial research · Sources checked October 13, 2026 · 4 sources
Stopping and reversing before 100 N on a 4 to 200 mm rod
US Federal Motor Vehicle Safety Standard No. 118 lets a power window, partition or roof panel close outside the listed conditions (key on, continuous switch hold and so on) only if it has an automatic reversal system. That system must stop and reverse before exerting a squeezing force of 100 N or more on a test rod placed anywhere in the opening. [1]
Atmel's AVR480 application note summarises the US and European rules (FMVSS 118 and 74/60/EEC) as a 4–200 mm detection area, 100 N maximum pinch force and reversal on a pinch, but it gives the test-object deflection ratios as 5 to 20 N/mm, lower than the 65 and 20 N/mm in the current US text; work to the regulation that applies to the vehicle. [2][1]
Editorial calculation: against a 65 N/mm rod, 100 N is reached after about 1.5 mm of glass travel beyond contact (100 ÷ 65); against a 20 N/mm rod, after 5 mm. The motor and its worm stage therefore have to be stopped within a millimetre or two of glass travel on the stiffer rods, which is why braking, gear backlash and the controller's sampling all count.
As open as when closing began; at least 125 mm more open than at reversal; or open enough for a 200 mm rod [1]
Infrared proximity systems
850–1,050 nm source, working from darkness to 64,500 lux [1]
Applies to
Passenger cars, multipurpose passenger vehicles and trucks with GVWR of 4,536 kg or less [1]
Tell the motor supplier whether the drive will be used with one-touch (express) closing, which regulation applies, and the glass travel per motor revolution of your regulator.
02
Reading glass position from Hall pulses and pinch force from motor current
AVR480 describes an anti-pinch system that uses a brush motor with two Hall effect sensors: the motor current, measured through a shunt, stands in for the force on the glass, and the Hall edges give position, speed and direction. One relay sets the motor direction and a MOSFET switches it on and off. [2]
The note models the window chain as motor, endless screw (worm), a flexible coupling, and a cable, pulley and roller regulator, and requires the detection to adapt because friction changes with ageing, wear, temperature, moisture and freezing. Its simulations inject a pinch with a 10 N/mm compression spring and a 50 N disturbance at 10 Hz to test that the algorithm reverses on the first and ignores the second. [2]
For the sensor end, Infineon's TLx4966xG double Hall latches put two Hall elements on one chip facing a rotating pole wheel and output either speed and direction or two speed signals, which Infineon says can be used directly for index counting in anti-pinch systems such as window lifts and sunroofs. The brief lists reverse battery protection to −18 V and peak temperatures up to 195 °C without damage, in TSOP6-6-9 and SSO-4-1 packages. [3]
Editorial note: a drive sold as "2-pin" has no position signal, so anti-pinch must rely on current ripple or a separate sensor; ask which variant the quoted price covers.
Ask for the number of Hall pulses per motor revolution, the pole-wheel and sensor arrangement (speed and direction, or two speed signals), and the supply and protection limits of the sensor output.
03
The self-locking worm stage, speed and variants of the drive
ZHAOWEI's window-lift worm gear motor is listed at 12 V nominal (customisable), 300 rpm ±10% no-load and 208 rpm ±10% rated speed, rotating both ways, with reduction ratios from 5 to 1,500 across its range and plastic or metal construction. The maker says the gear units are self-locking, preventing the window being forced open from outside, and offers 2-pin, sensor, slide-in and integrated-electronics variants with customer-specific interfaces to the lifter or door module. [4]
Editorial note: the published speeds do not state whether they are at the motor or after the worm stage, and no torque figure is given; for a regulator, ask for the output torque and speed at 12 V and at the lowest and highest battery voltages, the stall torque and current, and the holding torque of the self-locking stage.
Send the regulator type (cable or arm), glass mass, seal friction and travel time you need, so the supplier can match ratio, torque and current.
04
Data for a window-lift actuator motor
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Application: [window, sunroof or partition; one-touch closing yes or no; regulation]
Regulator: [cable or arm; glass mass; travel; target closing time]
Motor: [voltage range; output speed and torque; stall torque and current]
Gear: [ratio; self-locking holding torque; output interface]
Sensing: [none, Hall speed and direction, or integrated electronics; pulses per revolution]
Connector and housing: [connector; mounting; sealing]
Tests: [anti-pinch test with the regulator; durability cycles; temperature range]
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
What force limit does an auto-closing car window have to respect?
FMVSS 118 requires it to stop and reverse before squeezing a 4–200 mm test rod with 100 N or more. [1]
How does the window controller know where the glass is?
From Hall pulses: AVR480 uses two Hall sensors on the motor, and Infineon's TLx4966xG double latch gives speed and direction for index counting. [2][3]
Why use a worm gear in a window motor?
ZHAOWEI says the self-locking worm stage prevents the window being forced open from outside. [4]
Sources and what still needs a direct check
Sources checked 2026-10-13. The US regulation text (49 CFR 571.118, NHTSA), Atmel's AVR480 application note (now hosted by Microchip), Infineon's TLx4966xG product brief, and ZHAOWEI's product page for its window-lift worm gear motor.
