Richie: The £50, 3 week Featherweight

[Rapidrory]

Well the 3 Johnson 600's arrived. The build quality of them actually looks better than the 550's in the argos drills, so that's a good start.

They have a winding resistance of 0.2 ohms, as opposed to the 550's 1 ohm, giving it a stall current of 60A at 12v. This is understandable when you have a look at the windings; they're quite a bit thicker in the 600s, which also implies fewer windings as they're packed in the same space.

Idle current is about ~2A at 9.6V, which is what was quoted in the data sheet.

They are slightly longer than the 550, which is mostly down to the stronger bearing mounts, but there is a little extra length in the coils.

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Running on 12V, the 600 sounded about 30-50% faster, though I have no way to quantitatively test it atm.

Also seemed to have plenty of torque, though again, grabbing the output shaft with pliers is not a very accurate test. Did heat up quite quickly when put under load though.

The mounts at the front are a direct match to the 550, so the 600s can just be a drop in replacement

To summarise, these are very nice motors given the price, but I believe these are 9V motors of a similar nominal power to a 550 (relying more on current than voltage for its power). Therefore when you overvolt them to 12V you get more power, as you would overvolting a 550 on 16V. It will definitely make Richie's lifter faster (dunno about extra lifting power yet..), but that's only if they don't catch fire first... I will try installing one over the Christmas holiday.