Solenoid from a car door, any car door: are they legal in 2016?

[paul.dornfeld]

We want to hit a button on our joystick and activate a solenoid one time, quickly, to release the arm in the last 20 seconds. We have access to an old car-door electric lock solenoid and would like to use it. Can we just, "go out back" and take one out to use or must it be tested/certified somehow somewhere? Thank you.

[GeeTwo]

Q642:

Originally Posted by Q642

• Q. Does an actuator with an included motor sold as a "door lock actuator" meet the definition of "Select Automotive Motors" per R29 (sample: http://www.amazon.com/dp/B0088YE6YQ/)?
• A. Yes. As per the answer to Q626 , the intent of "Select Automotive Motors" is to limit the selection criteria of automotive motors to those specifically listed in the parenthesis that immediately follows. "Door" motors are listed, and a motor sold as a "Door Lock Actuator" does fall under that category.

Looks like a solid yes to me. You might want to take a picture of it in situ before removal as documentation in case an inspector asks, though they probably won't.

[paul.dornfeld]

Originally Posted by GeeTwo

Q642:



Looks like a solid yes to me. You might want to take a picture of it in situ before removal as documentation in case an inspector asks, though they probably won't.

Thank you for the clarification of the rules/quotes (very helpful) AND for the great suggestion of the photo.

[GeeTwo]

You're welcome, but thank team 1410 for the photo link. The link was part of the question they asked.

[Mark McLeod]

This covers it only if it is a motor, not if it is an electric solenoid.
Different rules apply.

[Al Skierkiewicz]

The correct quote would be from R29...
"Electrical solenoid actuators, no greater than 1 in. stroke and rated electrical input power no greater than 10 watts (W) continuous duty at 12 volts (VDC)."
You will need to document the part to prove to your inspector it meets this specification.

[Mr V]

If it is a door lock actuator from a car made in the last 40 or more years then that actuator will be a motor and not a solenoid and thus legal w/o restrictions. Now if is for releasing the trunk lid, hatch, or window in a hatch/tailgate then it will be a solenoid and legal if it is within the restriction of a maximum 1" stroke 10 watt consumption at a nominal 12v.

[paul.dornfeld]

Originally Posted by Al Skierkiewicz

The correct quote would be from R29...
"Electrical solenoid actuators, no greater than 1 in. stroke and rated electrical input power no greater than 10 watts (W) continuous duty at 12 volts (VDC)."
You will need to document the part to prove to your inspector it meets this specification.

Thank you much. Any idea how to go about documenting its 10 watt max draw?

[paul.dornfeld]

Originally Posted by Mr V

If it is a door lock actuator from a car made in the last 40 or more years then that actuator will be a motor and not a solenoid and thus legal w/o restrictions. Now if is for releasing the trunk lid, hatch, or window in a hatch/tailgate then it will be a solenoid and legal if it is within the restriction of a maximum 1" stroke 10 watt consumption at a nominal 12v.

Thank you for explaining the differences. How would I test for (and presumably prove for the inspectors) its 10 watt consumption, though?

[GeeTwo]

Originally Posted by paul.dornfeld

Thank you for explaining the differences. How would I test for (and presumably prove for the inspectors) its 10 watt consumption, though?

Power = IV = V²/R. If the resistance across its inputs is more than 14.4 ohms, you can probably use that as proof that the solenoid uses no more than 10W at 12V. If not, you'll probably need some more documentation from the manufacturer.

[EricH]

I would also attempt to find the model number and a spec sheet. Model number would likely be found on the device itself (if it survived the whole "being removed from the vehicle" routine) or in an owner's manual or repair guide (if you could find one that listed the parts). Once you have a model number, a bit of Google and you should have a spec sheet. I have yet to see an inspector debate a spec sheet that matched up to the component, unless the spec sheet showed the component was actually illegal.

[GeeTwo]

Originally Posted by EricH

I would also attempt to find the model number and a spec sheet.

At the least, note the make, model, and year that you are pulling the actuator from. Then, you can search some auto parts sites to identify the part that was originally there (or at least a suitable replacement).

[Al Skierkiewicz]

Paul,
First check for labeling on the device. It may just show current, we can work with that. The next thing would be to cross reference the device, somewhere there is likely a rating or an operational test that would indicate the actual current. I might even make a decision on current in use if all other avenues fail you. When I encouraged the GDC to adopt this in the rules, I referenced actuators that were in the then McMaster catalog.

[Richard Wallace]

Originally Posted by GeeTwo

Power = IV = V²/R. If the resistance across its inputs is more than 14.4 ohms, you can probably use that as proof that the solenoid uses no more than 10W at 12V. If not, you'll probably need some more documentation from the manufacturer.

An actuator rated for less than 10W electrical power consumption, continuous duty at 12VDC, might have a electrical resistance less than 14.4 Ohm when it is at room temperature. Conductors heat up while they are dissipating power, and their resistivity increases as they get warmer. Most solenoid actuators, and especially those made for use as car parts, are rated for operation while their conductors (and their electrical insulation systems) are quite a bit warmer than typical room temperatures. A room temperature resistance of 12 Ohm measured on an actuator that is rated for 10W at 12V would not surprise me at all. If the insulation system is rated for under-hood automotive applications, 10 Ohms would not be unusual.

[GeeTwo]

Originally Posted by Richard Wallace

..Conductors heat up while they are dissipating power, and their resistivity increases as they get warmer. ..

Agreed, and further, because the peak power output is usually around half speed, where the back-EMF is half the input voltage, the continuous power draw is even less. My point was that if the resistance was 14.4 ohms or higher, the device could not dissipate/convert a total of more than 10W. The actual resistance of a 10W motor could be much lower.

For example, the static resistance of a CIM is around 0.09 ohm, which tells you that its maximum power is no more than 144/0.09 = 1600W. The rating is about 337W.