Correct ESC?

[David Marks 2Participant @davidmarks2]

[David Marks 2Participant @davidmarks2]

I am currently building a Plaudit tug (hull length 27inches) to which I have fitted a 540/1 type motor operating on 6V via a P92 Power Distribution Board. I have "in stock" an Action Electronics P79 Condor 10 ESC which I would like to use. The alternative is the P80 Condor 20 which Component Shop is currently showing as "out of stock". Will the Condor 10 be suitable to use?

[ashley needhamParticipant @ashleyneedham69188]

David. What size prop are you going to use?? If its not too big, I would not have thought that a 540/1 will not draw too much current especially on 6V. Easy enough really to just put a battery across the motor once it is in the hull, in water, and measure the current, then decide?? Ashley

[Malcolm FraryParticipant @malcolmfrary95515]

What Ashley said, just hook the motor to the battery via a fuse. If it doesn't blow a 5 Amp fuse, your ESC will be OK. Alternatively, if you have an ammeter, connect that in place of the fuse and read the current.

[David Marks 2Participant @davidmarks2]

Ashley/Malcolm – The prop size is 50mm (as per the drawing). I will try testing using a fuse. Many thanks.

[ashley needhamParticipant @ashleyneedham69188]

50mm may be a bit big for that motor depending on the pitch.

​I purchased some 4-blade plastic props YEARS ago and found they were a very fine pitch….and thus far I have not found a use for them! A brass 3 or 4 blade might strain the motor somewhat but you may get away with a plastic 3 blade one .

HOWEVER the proof is in the eating (or woteva) so give it a go first.

​Ashley

[Dave MilbournParticipant @davemilbourn48782]

David

The rule of thumb for brushed motors is not to fit a prop which is larger in diameter than the case of the motor or has more blades than the motor has poles on its armature. A 3-pole 540 is approx 38mm while your prop is 50mm. There are exceptions e.g. a 555 will produce a lot of torque at low revs and will be OK on a 50mm prop, but a 540/1 is really too fast-revving. By all means give it a bash as suggested but I think you'll find that the motor will draw a lot of current under load. I would fit either a 555 or a 540LN and use the P79.
I think that Iain Lewis was planning an update to the P80 which involves a BEC, but so far nothing has happened. I'll give him a nudge because meanwhile he's not selling P80 and I have parts here for 20 of them minus the PCB's – that's if I can ever find them after the house-move!

Dave M

[David Marks 2Participant @davidmarks2]

Gentlemen – Thank you all very much for your interest and help. I have decided to purchase a 540LN motor which at around £8 provides a cheaper solution than purchasing a P80 ESC. I was aware of the guidelines for matching the prop diameter to the motor case size but the 50mm does look about right for that particular model although the actual specified motor is a 545 Monoperm which is no longer available.

[David Marks 2Participant @davidmarks2]

I am in the final stages if building the model previously described. I have fitted a 540LN motor which I am running on 6V via a P79 ESC. However this gives an extremely slow prop speed, in fact so slow that If I wanted I could count the revs against a stop watch. However, connecting the motor direct to the 6V battery, the prop speed is "as expected". Does anyone have any idea of what is causing the dramatic reduction is speed when using the P79 ESC! Many thanks in advance for you anticipated help.

[Dave MilbournParticipant @davemilbourn48782]

Check that the little jumper is set to Linear and not Slow Start. If that doesn't sort it then see if you can count the number of poles on the armature of the motor by looking through the cooling slots in the shaft-end. If it's more than 5 then you need a P79S.

[Dave MilbournParticipant @davemilbourn48782]

I've just checked the MFA datasheet for 540LN and found that it's a 5-pole motor, but the maximum speed with no load that you can expect on 6v is just 3000RPM. I think I may have a 540LN motor; if so I'll conduct some tests with a P79 and let you know what I find.

Dave M

[David Marks 2Participant @davidmarks2]

David – Like yourself, I checked the spec of the motor re. the number of poles. I moved the jumper within the ESC to the Linear position and found that the speed had increased but nowhere near to the speed of the motor when run direct from the 6v battery. However, the speed may be sufficient for the particular application for which it is to be used. I am going on holiday for just over a week and will conduct a pond test on my return. I would be interested in the results of you test.

Regards – David Marks

[Dave MilbournParticipant @davemilbourn48782]

David – Sorry, but what I actually had was a 540LN box with a straight 540/1 inside!

DM

[David Marks 2Participant @davidmarks2]

I have undertaken a further test of the set-up using the P79 ESC. I uncoupled the 540 LN motor and in its place connected a 540/1 motor. This gave an acceptable shaft speed although I did not connect the 540/1 direct to the 6V battery to establish if there was any reduction in speed between running direct from the battery or through the ESC. I can only assume that the 540LN motor is not compatible with the P79 ESC.

[Dave MilbournParticipant @davemilbourn48782]

David

I have tested your motor and ESC, and sent you a private message.There is no incompatibility problem and the speed controller works as it should.

Dave M

[Author]

Posts