Servo, IONI and PSU selection guide

@phillip.vanrensburg Do you think you can share the link to the spreadsheet you are using? It would be helpful to actually learn how the values are calculated and calculate them for other servos… Thanks! :slight_smile:

Eh…

^^That’s correct, not a mistake :wink:

Error 404 on the link on OP.

Of course Dropbox kills the link after a period of time…

Does anyone have a mirror of the PDF Beano posted?

Is this what you want?

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Hello, is it possible to get the spreadsheet so I can add my own motor to see estimation for needed PSU wattage? I tried to use formula from wiki but the result does not seem right to me. I’m trying to calculate PSU for Lenze MCS 12D20L which is in datasheet pretty much next to 12H15L which is already included in the table.
Here is screen from datasheet:


I will be using IONI Pro HC.
Thank You.

Peak Current squared * phase to phase resistance * 1,5 = 1034W for this motor and this does not include the shaft output power.

I wouldn’t say that this is very good motor for this purpose. If you’re willing to pay this amount of money for a motor, I would recommend to purchase Simucube 2 Ultimate or Simucube 2 Pro. You will get better performance either way.

Thank You. I managed to get this motor for about 100 EUR almost unused. So I would say that it is not a bad deal. I will probably end up using something around 750 W PSU. I know there will be some performance left on the table but as the motor was almost the cheapest thing on my setup I’m willing to upgrade it later if I found it lacking.

PS: Before I picked up the motor I calcualted based on formula from wiki (https://granitedevices.com/wiki/List_of_motors_for_SimuCUBE):

Max_torque_output = torque_constant * (32.2 / winding_resistance) [Nm]. The 32.2 is the maximum phase-to-phase RMS voltage with a 48 V PSU.
PSU_requirement = (max_torque_output/torque_constant)^2 * winding_resistance * 1.5 / 0.93 [W]. Replace the max_torque_output with the motor peak torque, if the latter is smaller.

Max torque = 1,16*(32,2/2,2) = 16,98 Nm
PSU_requirement = (16,98/1,16)^2 * 2,2 * 1,5/0,93 = 760 W

I have some electrical knowledge but not in terms of motors so I’m now confused about why there is not just this simple formula on the wiki?

The same formula is there in wiki and you used the same formula, except that I happened to use it wrongly as I did not check properly the peak current the drive can drive through the motor, therefore my result was too high.

Same formula, but with the actual peak rms current check.