One big transformer or three?

[koslaz]

Guys, which is the best practice for power supply?
One big transformer for three servos,
or one dedicated for every servo?
What's the pros and cons of every solution?

Thanks.Any help would be appreciated.

[CJL5585]

Guys, which is the best practice for power supply?
One big transformer for three servos,
or one dedicated for every servo?
What's the pros and cons of every solution?

Thanks.Any help would be appreciated.

A simple question would be easier to answer.

Planning on buying or building a power supply?

If buying:
Voltage and current requirements might result in a very, very expensive power supply to power all the servos. Same goes for seperate supplies for each servo. Determining factor is Voltage and KVA rating.

If building:
It might be more economical to build a supply for each servo according to the voltage and current requirements, especially if the voltage is something of a standard value, and the current required is 15 amps or greater per servo.

If the total current required for all servos is 30 Amps or less, this can be accomplished with a single power supply. It normally is not economical to build supplies larger than 30 Amps. If more current is required, the best route is to parallel identical power supplies.

Space available:
Is un-limited space available for this power supply/ or power supplies. Space required will determine whether one or multiple transformers are used. Also, One also must have space for fuses, rectifiers, and filter capacitors.

These are some factors which must be considered. Sorry, I could not fully answer your question.

Hope this helps in your decision.

[NC Cams]

Do the math.

The cost of 3 small tranformers versus 1 big one.

Three diode bridges and capacitor banks versus 1 bigger set.

Three times as much stuff to package and go wrong as opposed to 1 set along with the added complexity of stuff to go wrong and/or malfunction.

The cost to upgrade from say a 10 amp tranformer to one 2-3 times the current capacity probably won't triple. However, spending the money for diodes and capacitors and wiring generally WILL.

If you're trying to save money, you WILL HAVE to price out the parts and the labor differential to determine the REAL answer/benefit. If you can get the stuff cheap, that's one thing but if you have to buy everything new or even surplus, it all comes down to doing the math.

T'were it me, I 'd build 1 because it is simply less work and packaging to deal with.

[pastera]

One transformer - You will normally not be pushing all three axis' at max and can rate the transformer at approx 3x+10% of the highest servo running current. You don't need to rate for peak current as you will not be able to run your servos at peak for more than a very short time (<<1 min). The transformer can handle short overloads just as the servo can.
You don't really need to rate for 3x continous current as you would normally not be running all three axis' at max for any length of time.

Aaron

[koslaz]

Thanks for the help guys
and excuse me for not being to clear.
I'm planning to build the PS.
The maximum continuous current is 10.2 A
and the maximum voltage is 60 V.
And I planing to running them at 50 V
I guess I'll go for one big transformer.
1500 VA would be good or I can go with
a smaller one?