Quote Originally Posted by Christian Knuell View Post
Hi,

there are no big price differences between toroid and switched-mode power supplies anymore.

I'd always use a switched-mode power supply for CNC machines because they offer some advantages:
  • You get a finished, reliable product - no need to choose components and solder them together.
  • It won't blow your fuses from time to time like many large toroids do if you don't use a current limiter.
  • Most Important: Load and idle voltage is constant. With a toroid you have to take care to keep idle voltage below the drivers maximum voltage rating - but once the machine starts running this voltage will drop and you won't get the maximum speed and dynamics you'd get if you use a switched-mode power supply.


Christian
This is taken from the Leadshine drive manual:
Regulated or Unregulated Power Supply

Both regulated and unregulated power supplies can be used to supply the drive. However, unregulated power supplies are preferred due to their ability to withstand current surge. If regulated power supplies (such as most switching supplies.) are indeed used, it is important to have large current output rating to avoid problems like current clamp, for example using 4A supply for 3A motor-drive operation. On the other hand, if unregulated supply is used, one may use a power supply of lower current rating than that of motor (typically 50%
～70% of motor current). The reason is that the drive draws current from the power supply capacitor of the unregulated supply only during the ON duration of the PWM cycle, but not during the OFF duration. Therefore, the average current withdrawn from power supply is considerably less than motor current. For example, two 3A motors can be well supplied by one power supply of 4A rating.

It is generaly accepted that unregulated power supplies handle back emf better than regulated.

Hi Clive the links don't work any more they changed the site. Also I don't need 50v that's a bit much for my drivers.
The links still take you to the company and with the part No's. in the link they still work if you do a search on the site. Also I did point out that you had to pick a transformer to suite the voltage you require. Not forgetting to times the voltage of the TX by about 1.4 to get the DC voltage you will get. ..Clive