Hi, I am very new to this site, but I am currently completing first year mechatronics and have become stuck with creating the right voltage for a particular motor. We are building a crane and I have designed trolley system around this really small hi-torque motor that runs at max eff= 1.5v @0.16A and the power supply is set to 24v and we can not use any batteries. I have designed the circuit below (sorry about the crappy schematics) to use on the 3 motors, with just inserting the appropriate value zener diodes for voltage (12v & 4.5v) and resistors to limit current. But as I am finding out now is that 1.5V zener are pretty much impossible to get, well at least within the next week and a half anyway.
I know a simple resistor voltage divider circuit wont work because the motors fluctuating impedance, I have found 1.5V voltage regulators but I don't know if this can be used in the same way as the zener. I also thought of this way (second pic) but I dont know about voltage regulators at all.
Any suggestions or help would be great! If your from Australia/Brisbane any suggestion of parts I could pick up from places like jaycar would be amazing considering the tight time schedule.
cheers
EDIT: 1.5V voltage regulators also seem like they are hard to come by.

 

I would use a buck regulator like the Lm2596,

http://www.ti.com/lit/ds/symlink/lm2596.pdf

on Ebay Australia
http://www.ebay.com.au/itm/LM2596-V...23?pt=LH_DefaultDomain_15&hash=item25a65dcaff

or
you could use a Lm317 variable regulator set it to 1.5v, its minimum output is 1.25v, but at that voltage drop with 0.16 amps you would need an heatsink it will be giving out 3.6W, or simple transistor and diodes, what ever method you use your dropping 22.5V @ 160mA,

 

My offering:

Edit: You would need a power transistor with a heat sink.

 

A switched-mode DC converter is the most efficient way to drop the voltage. Any linear voltage-dropper/regulator is going to dissipate quite a lot of heat (at least 3.6W for each motor load). Here's one option for a linear regulator:

 

Thanks heaps for all the help everyone! I have decided to swap the motor, after investigating this suggetions further, it was starting to over complicate the design. Its not very pretty but it works.