Power Supply Suggestions please..

[Jonathan]

i will be running other things requiring voltages less than 50v so this should cover the lot.

Then you should use the right size (750VA for 5 motors) transformer for the motors and get transformer(s) with lower voltage windings to power the lower voltage appliances, otherwise you've got to somehow drop the voltage further which is complicated to with any efficiency.

ok I decided on going for this one: Standard Range Toroidal Transformers: CM1200171: 1200VA 230v to 120v

Er, I hope not as that has a 120V secondary not 50V or 25+25V which is what you need for the motors.

its not as big as the other one but then i Bought two!!

So you'll have about 1.65kW surplus after powering the stepper motors - must be planning some pretty serious optional extras to use that much. Perhaps the machine is going to make tea...

[Ricardoco]

Er, I hope not as that has a 120V secondary not 50V or 25+25V which is what you need for the motors.





So you'll have about 1.65kW surplus after powering the stepper motors - must be planning some pretty serious optional extras to use that much. Perhaps the machine is going to make tea...

Erm Not Sure what happened there here is the actual ones i have bought...

CM1200424 - Standard Range Toroidal Transformers
Product Description: 1200VA 230v to 4x24v

Is that better???


Rick

[Jonathan]

Yes that's better, still seems OTT though. 4x25v would have been slightly better, but it's not a big deal.

With that transformer you will be able to get multiples of 35V, so 70V for the motors and 35V for other things. What voltage do the other things require?

[Ricardoco]

Yes that's better, still seems OTT though. 4x25v would have been slightly better, but it's not a big deal.

With that transformer you will be able to get multiples of 35V, so 70V for the motors and 35V for other things. What voltage do the other things require?

The other things range from 12v to 32v but the contactors can be what ever i want when i order them.

[Jonathan]

The other things range from 12v to 32v but the contactors can be what ever i want when i order them.

Presumably the contactors are just to switch these other things on and off?
The absolute minimum you can get from the transformer you have bought is by using one 24v winding, which when rectified will give 24*2^0.5-1.1=32.8V which is clearly above 32V so probably not much use. Also the tolerance on the mains voltage (230V +10% - 6%) means that it could be up to 32.8*1.1=36.1V.

How much power do these other things need? Can you provide a list of voltage and current or power that each device uses so we can work out the best transformer? It sounds like you'd be much better off with a separate transformer, perhaps 16V.

[Ricardoco]

Presumably the contactors are just to switch these other things on and off?
The absolute minimum you can get from the transformer you have bought is by using one 24v winding, which when rectified will give 24*2^0.5-1.1=32.8V which is clearly above 32V so probably not much use. Also the tolerance on the mains voltage (230V +10% - 6%) means that it could be up to 32.8*1.1=36.1V.

How much power do these other things need? Can you provide a list of voltage and current or power that each device uses so we can work out the best transformer? It sounds like you'd be much better off with a separate transformer, perhaps 16V.

If i was comming out and used non regulated that would be a problem but i will build a circuit to give me all the voltages i will ever need. Besides which they are on their way to me this moment.

rick

[Jonathan]

If i was comming out and used non regulated that would be a problem but i will build a circuit to give me all the voltages i will ever need. Besides

The problem is unless it's less than a couple of amps it's hard to regulate the voltage, since linear regulators are extremely inefficient so you can only use them for quite small currents, SMPS's are quite difficult to design and adding more transformers is rather illogical, so I'll be interested to see how you plan to change the voltage. Also if the other appliances only use a small amount of current (making it reasonable to use linear regulators), then the transformers are probably several times bigger than they need to be.