Help Building 0-24 volt 5amp power supply

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brooksmeyer

New Member

• Nov 4, 2012

• #1

Hello I am new to this world and I want to build a 5amp adjustable 0-24 volt power suppley.

I fould plans for a 2amp version of what I want to build but it is only for a 2amp power supply. The power supply I want to build will be used to power a HO slot car track.

I have provide a link to the design and I just need help on what parts do I need to upgrade to beef this up to a 5amp unit.


https://makeprojects.com/Project/0+-+24+Volt,+2+Amp+Bench+Top+Power+Supply/1428/1

Thank you

 

Vizier87

Active Member

• Nov 5, 2012

• #2

You can use this component.

There is a circuit in the datasheet which can guide you to build it. Hope this helps.

 

crutschow

Well-Known Member

Most Helpful Member

• Nov 5, 2012

• #3

Be aware that a 5A, 24V linear power supply can dissipate up to 120W so you need to use a very large heat sink to keep the regulator from overheating.

 

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brooksmeyer

New Member

• Nov 5, 2012

• #4

Thanks for the input so far. Question would I have to use a large heatsink if I use a fan in the case?

Also is I were to add a fan any sugestion where to put it.

Thanks

 

ronv

Well-Known Member

Most Helpful Member

• Nov 5, 2012

• #5

If it is to run slot cars you don't need a regulated voltage. You can use the 5 amp transformer and bridge rectifier. A filter cap of say 2200 Ufd. might be a good idea. I would oversize the bridge rectifier for maybe 30 amps and add a thermal circuit breaker as slot tracks are prone to shorts.

 

crutschow

Well-Known Member

Most Helpful Member

• Nov 6, 2012

• #6

ronv said:

If it is to run slot cars you don't need a regulated voltage. You can use the 5 amp transformer and bridge rectifier. A filter cap of say 2200 Ufd. might be a good idea. I would oversize the bridge rectifier for maybe 30 amps and add a thermal circuit breaker as slot tracks are prone to shorts.

Click to expand...

The OP stated he wanted a variable 0-24V supply.

 

alec_t

Well-Known Member

Most Helpful Member

• Nov 7, 2012

• #7

Wouldn't a fixed 24V with PWM give better control for slot cars?

 

ronv

Well-Known Member

Most Helpful Member

• Nov 7, 2012

• #8

Most (all) of the slot cars I have seen use a fixed voltage supply and some sort of hand held controller to control the speed of the cars. Is this how yours work?

 

audioguru

Well-Known Member

Most Helpful Member

• Nov 7, 2012

• #9

The 24VAC transforer feeding a fullwave bridge rectifier produces 32VDC which is much too high.
A 24V regulator needs only 27V as the input so the remaining (32V - 27V=) 5V is wasted as HEAT.
Use a 20.5VAC transformer instead.