Replacement fan for Ormerod 1 hotend

So like an idiot I accidentally stuck the end of my needle nose pliers into the fan of my ormerod while it was running, and the result, predictably, is now a broke vane on the fan.
Since I need to replace it anyway, I figured I might as well upgrade to a PWM fan, but the examples on the forum all refer to 4-wire fans, and the ones I can get locally all have 3 wires.
I can get the following fans locally, would either one of them suffice as a replacement?

http://za.rs-online.com/web/p/axial-fans/0426358/

http://www.3dprintingstore.co.za/electronics/fan-40mm-x-40mm-12v-sunon-maglev-bearing/

If you mean the hot end cooling fan, don't use a PWM fan. That fan should be running whenever the hot end is above about 40C, otherwise you are likely to get a nozzle blockage.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Ah! Thanks for the clarification DC.

On a side note, using your IR sensor, I find the fan comes on intermittently even when the hot-end temp is around 21. It seems related to the LED on the sensor coming on. Is this by design, or do I have a short somewhere?

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pandionx
Ah! Thanks for the clarification DC.

On a side note, using your IR sensor, I find the fan comes on intermittently even when the hot-end temp is around 21. It seems related to the LED on the sensor coming on. Is this by design, or do I have a short somewhere?

Could be a short, or possibly a poor connection to the board. Can you induce the fault by waggling the cables attached to the board? It is essential to provide strain relief for the cables, otherwise the constant flexing as the head moves along the X axis will break them at where they enter the crimp pins.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

It looks like the issue was due to a bad connection I made to the Molex connector. The new fan does not exhibit the problem.

DC, just to clarify - you say not to use a PWM fan. The fan speed setting on the firmware/web interface, is that then for additional fans you mount for active cooling?

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pandionx
DC, just to clarify - you say not to use a PWM fan. The fan speed setting on the firmware/web interface, is that then for additional fans you mount for active cooling?

That's right, it's for a print cooling fan connected to the FAN0 pins of the Duet. The hot end fan needs to run whenever the hot end is above about 40C. That's why it is normally connected directly to the supply voltage.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].