1 Topic by IFLS

  • IFLS
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Topic: Blue and Grey wires on power supply, which is the positive?

I ran into a problem with the filastruder assembly, after I cut the power supply wire where the instructions said to I found a blue wire and grey wire, not the standard red and black. I know the instructions say to use to volt meter to check this but I have no idea how to do that, even though I have one sitting here. Any help is appreciated, thanks.

2 Reply by elmoret

  • elmoret
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Re: Blue and Grey wires on power supply, which is the positive?

Its funny, power supply manufacturers seem to use any random color that's in the shop, so it does vary - that's why I only mention the standard red and black.

To test:

Connect a probe from the meter to each wire. Check that the probes are connect to "V" and "COM", not "A". Set the meter to the 20vdc scale (I am guessing your meter here, a picture would help). Plug in the power supply, you should get 12.xx volts. If there's a minus in front of the reading, then the wire connected to the red probe is negative. Otherwise, the wire connected to the red probe is positive.

The only thing that cares about polarity is the fan. The PID controller, heater, and motor do not. The motor does need to rotate the correct direction (CW as viewed from the hot end) but otherwise, everything's tolerant. I think the fan just doesn't spline if you hook it up backwards.

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

3 Reply by IFLS

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Re: Blue and Grey wires on power supply, which is the positive?

Here is my volt meter: southwiretoolsDOTcom/tools/tools/10010S


Also, was the kit supposed to come with wire for this or should I just cannibalize old chords from storage? Thanks for the quick reply

4 Reply by elmoret

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Re: Blue and Grey wires on power supply, which is the positive?

http://southwiretools.com/tools/tools/10010S

Analog voltmeter - I haven't seen those in a decade! You can get a nice digital one from Harbor Freight for $4.

Anyway - set it to 50vdc. if the needle moves to ~12v, then the wire attached to the red probe is positive. If it tried to move backwards. then the wire attached to the red probe is negative.

You're supposed to cut the power supply's DC side about a foot from the power supply, and use the remaining cable for wiring switches and the motor, as mentioned in the instructions:

2.)    Cut the 12v cable coming out of the power supply approximately 12 inches away from the power supply. The 12v cable is the one that does not plug into the wall.

You can also use old cords from storage, as long as they are at least 18AWG.

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

5 Reply by o5techman

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Re: Blue and Grey wires on power supply, which is the positive?

Go to  allaboutcircuits.com/vol_5/chpt_2/2.html#wire.tbl

They have a very comprehensive list of countries and their color schemes!

International Electrical Code  says:    Blue = (+) and grey = (-).

Meters are best.

Joe