100VDc generation for CNC PLC. 20+ amp capacity?

It looks like you are getting the hang of it. A few things to remember about transformers.

The output voltage as a direct ratio to the input voltage and equal to the ratio of the number of turns on their respective windings. You can use a transformer to generate a different voltage than the plate voltage. i.e. a 120 volt in/80 volt out has a ratio of .666:1 and will also work as a 100 volt in//67 volt out. The maximum current rating remains pretty much the same as it is determined by the ability to dissipate heat, core losses, and resistance of the windings. Multiple transformer outputs can be wired to add or subtract, when connected together, depending upon whether they are wired in phase or out of phase.

If you have not found the solution yet, look at isolation transformers on e-bay in business and industrial. I had seen some isolation transformers there with 120/208/240 in, and 120/208/240 out. Running 120 on the 240 in winding will give you 104 out on the 208 out winding. They are fairly common in industrial environments where they have 3 phase and want to develop a true 120-0-120 circuit. Just remember that you will have to derate the power by 50% if running on half voltage.

Good luck!

Bob
 
Just to clarify this in my mind... is this DC supply to be used to operate a DC servo motor?
The power supplies for DC servo motor DRIVERS (the electronics that takes step & direction input and operates the servo motors) do not need to be regulated other than limiting the maximum input voltage. The DRIVER itself IS a voltage regulator.

paul
 
Yeah- you have it right as far as I know. But- On the Ajax inputs, they advise the following:
a) Do not exceed 155VDc on the H2 input as the current/voltage source input for their internal servo driver.
b) They do not regulate in anyway- They advised me to try and match the H2 input Vdc source as close to the Motor spec as possible.

Just passing along what I was told. Q&A alway's welcome on this stuff! so thanks!
CG.
 
A fullwave bridge rectifier will have a peak voltage output of about 1.4 times the RMS value fed to the rectifier. Especially with a filter capacitor on the output.

How much the voltage 'sags' will depend on the current capacity of the transformer and also on the current load and the size of the filter caps.

The peak voltage from your 67 VAC supply, which is measured with a typical RMS reading voltmeter, will have a peak value of about 97 VAC and when rectified the DC voltage will be higher than the obvious and expected 67 volts DC volts.

While 'they don’t regulate in anyway' is one way of looking at it, the servo drivers are essentially continuously adjustable voltage regulators that output a voltage based on what the encoders and the controller is telling it to do. What your guys are telling you is not to exceed 155 volts open circuit. You may not need anywhere that high a voltage for your application. If your voltage is to low your rapids may well be slower than you would like, but things will still move.

I don't own any part of these guys, http://www.antekinc.com/, but I have used their transformers and power supplies. This one is in my unfinished CNC project.
Tooo may hobbies...

paul
 
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