I have two AC / DC adaptors.

Model SY-002-5-12 Output 12V_...2A 5V_...2A and

Model LX1205 Output 12V_...5A

Only the 12V _2A will run the motor.

What am I missing? I thought the 12V_5A would be the better choice as a power window motor usually runs around 12V_5A.

Help please.

  • \$\begingroup\$ Have you measured them? With a load? \$\endgroup\$ – Ignacio Vazquez-Abrams Dec 23 '16 at 0:23

Regardless of load, any motor will draw a high current (4X to 10X normal), when power is first applied, before the shaft starts to turn. Depending on motor type, design details and load characteristics, the current will drop to normal in milliseconds to seconds. It is likely that your 2A power supply tolerates the initial current while the 5A supply is shut down very rapidly by its electronic protection circuits. Since it does not appear to be well protected and it is not rated for the expected motor current, the 2 A supply is likely to fail fairly soon if you continue to use it.


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