Unregulated Linear Toroidal PSU Build

[Baja-king]

Just planning a build of a PSU for a Warco WM18B mill conversion using Teknik Servo motors.

According to their guide https://www.teknic.com/selecting-power-supply/ 75VDC is the sweet spot for their motors.

AC is around 232v in my neck of the woods (Cardiff) so I came up with the following spreadsheet for available Airlink Transformers:

29764

Now my question is do I go for the 25+25 (in series) 750VA or do I go for the 55+55 (in parallel) 750VA

The motors are good to 90VDC so even at 250VAC input the 55+55 would equal a no load of 86.8VDC

Will Back EMF be a problem? will be using suitable bridge rectifier and capacitors of course.

Thanks in advance

[Voicecoil]

Back EMF needs to be considered, I calculated it on my machine as about 7V - but it depends on the amount of energy in the machine and the size of your reservoir cap(s).

[Baja-king]

Back EMF needs to be considered, I calculated it on my machine as about 7V - but it depends on the amount of energy in the machine and the size of your reservoir cap(s).

Thanks, how did you calculate it? theoretically or practically.

[Voicecoil]

Theoretically - I worked out the energy in the moving system then using U = 1/2*C*V2 calculated the voltage rise on the cap.

[Baja-king]

Thank you

[Baja-king]

Decided to go with the CM0750255 (http://https://airlinktransformers.com/product/chassis-mounting-toroidal-transformer-standard-range-cm0750225)

750VA 25 + 25 in series, I don't think the 2-3 volts are going to be noticeable and I'd rather have the headroom on the bus voltage.