Wiring drives (24v power) in series or parallel

[watsonstudios]

I was wondering if anyone out there could tell me the difference between wiring up the power supply to the drives in series or parallel. I have 4 drives,
and a 24v 4.5 amp power supply

Which is recommemnded?

I don't know which method effects current(amps) and voltage

series: 24v to all drives but shared (divided)current?
parallel: 4.5 amps to all drives but shared voltage (6 volts per drive)?
Is this correct or is it the other way around?

Which way gives more speed but less current per drive?
-or-
gives more current(for torque) and less speed(voltage) per drive?

I would rather have power than speed. how can I get more amps to the motors?

[Al_The_Man]

Drives can never be series up, always connect in parallel, with a separate supply to each from the power supply.
Al.

[watsonstudios]

Thanks, good to know before I blow anything up.

[gar]

070627-1445 EST USA

watsonstudios:

I do not believe you understand the meaning of series and parallel based on your comment:

"series: 24v to all drives but shared (divided)current?
parallel: 4.5 amps to all drives but shared voltage (6 volts per drive)?
Is this correct or is it the other way around?"

A series connection is where a second terminal of a first device is connected to a first terminal of a second device, and the second terminal of the second device is connected to the first terminal of the third device, and so on. In this case the first terminal of the power supply is connected to the first termianl of the string of series connected devices, and the second power supply terminal is connected to the second terminal of the last serial connected part. In other words there is only one loop path.

In a simple series circuit the same current flows thru each component in the series connection. In a DC circuit the voltage across each element in the series path has a value Vi = Ri * I. The sum of the Vi s will equal the power supply voltage. Suppose there are three resistors in series and the resistances are 1, 2, 3 ohms. The total series resistance is the sum or 6 ohms.

Connect this series of three resistors to a 6 V battery. The current flow is 1 amp. The voltage drops are 1, 2, 3 volts. Now connect the same series resistors to a 12 volt batery. The current is 2 amps, and the voltage drops are 2, 4, 6 volts.

A parallel circuit is where all first terminals are connected together, and all second terminals together. The conductance of the parallel combination is 1 + .5 + .3333 = 1.8333 mho, and the resistance is the reciprocal of conductance or 0.5455 ohms. The total current from 6 volts is 6/0.5455 = 10.99 amps. The individual currents are 6/1 = 6 amps, 6/2 = 3 amps, and 6/3 = 2 amps and the sum is 11 amps which agrees with the above calculation. In the parallel connection there are multiple loop paths.


In a series connection the same current flows thru each element in series. The voltages across each element may or may not be the same, depends upon the values of each resistor. But the sum of the voltage drops in the resistors will equal in magnitude the source voltage. But the source voltage is of opposite polarity relative to the resistors. This is so the sum of all voltage drops around a closed loop are zero.


In a parallel connection the same voltage is applied to all parallel elements. The current in each element is determined by its resistance and the source voltage. The sum of all load currents is equal in magnitue to the current from the voltage source. However, at any node the vector sum of the currents is 0.

A copy of the "Radio Amateur's Handbook" may be a useful source for you to study basic electrical theory.

.
.

[probinson]

As Al_The_Man said, you can't put drives in series. The current is equal through all parts in a series circuit so which ever motor was requiring the least amount of power would get all the voltage and the others would have none.

If you need more current you can use parallel power supplies.

If you have unregulated supplies (simple transformer, rectifier, and filter capacitors) then they can be connected directly together in parallel.

If you have regulated supplies then it gets complicated because you will need some sort of load sharing circuit. This could be as simple as a series resistor on each supply or as complicated as a current mirroring system.