I'm trying to use an industrial camera lens that has two internal motors. One is for zoom, with DC voltage, reversible for direction. The other motor is for the shutter. It is presumably a stepper. it has 6 wires going to it. Resistances between the wires is 136 Ohm between red and orange, 1.47kOhm blue/black and 760 Ohm brn/red. All other combinations show as open connections. The resistor in the center has a color code of 680 Ohm.

Using 9 Volts, connected to orange / yellow (gnd) opens the aperture fully. Reversing the voltage makes a noise like it wants to close the aperture further. Connecting red / brown (gnd) also opens the shutter. Reversing does not make any noise. No other combinations do anything.

Is this a stepper motor? What would a schematic of the motor look like?

Aperture motor hookup

  • \$\begingroup\$ Shutter is a linear motor or solenoid, perhaps dampened by the R in series ton V+ and two coils for direction pulses to gnd and the motor is probably quadrature 2 phase using 2 half bridges. \$\endgroup\$ Commented Apr 7, 2021 at 1:38
  • \$\begingroup\$ Title says Aperture, body says Shutter. Which is it? Shutters are only meant to open fully or close, and those blades look like shutter blades. So that may be a simple solenoid or voice coil. \$\endgroup\$
    – user16324
    Commented Apr 7, 2021 at 13:57

1 Answer 1


There are a couple of resources on the net about identification of stepper wiring. The most common are 4 and 6 wires (6 wire being the almost universal wiring).

There is another kind of actuator you are likely to see in a camera, a voice coil: put a current and something moves depending on how much current you give (microamps, usually). It's actually one of the fastest electric actuator around (hard disk heads and laser scanners are done in this way). Your shutter seems to work this way, try putting an intermediate amount of current to see if it goes halfway


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