Advice on buying servos.

[Agathon]

There are a few reasons, but this one normally gives you an indication.
Ok, lets say you have a machine with 8 axis and each axis needs a servo, that is not too large.
you can get 8 AC servo motors and driver and you will be paying more because each driver has its own power supply.
with the DC option, you will have 8 DC servo drivers and a large power supply.
Also DC servo motors are typically low voltage DC, so the current is higher, so typically the motors dont go too big (under a KW)
Personally, i would not even consider a DC servo system, unless you know why you need it. AN ac servo system is typically a better option.

Right, so AC servo drivers aren't typically 240vac SP input then and need a step-down transformer?

[Gary]

No, AC is AC, regardless of the voltage.
Typically single phase goes up to about 1.5KW
For a hobby machine, its unlikely you will need anything that big.
Even a mill like Bridgeport MDI /Interact can use 750W easily.

Right, so AC servo drivers aren't typically 240vac SP input then and need a step-down transformer?

[Agathon]

No, AC is AC, regardless of the voltage.
Typically single phase goes up to about 1.5KW
For a hobby machine, its unlikely you will need anything that big.
Even a mill like Bridgeport MDI /Interact can use 750W easily.

OK, so just to be clear. A 400W AC servo motor would typically be coupled to a driver powered by AC at a voltage less than 240v? So is the power supply simply a step-down transformer or is there more to it?

[Gary]

it totally depends on what the bus voltage of the motor is.
To make it easy, if and when you buy them get a matched pair with cables, or talk directly to the company and get advise on what they suggest for the application.

[Agathon]

it totally depends on what the bus voltage of the motor is.
To make it easy, if and when you buy them get a matched pair with cables, or talk directly to the company and get advise on what they suggest for the application.

Thanks - I'll email you in the next few days.