110V to 24V Transformer - Page 1
Forum section: electronics / beginners

author: Izzy
author_rank: Newbie
timestamp: January 12, 2019, 02:24:57 pm
content: Hello, I'm working on converting an electric wheelchair to a trailer moving dolly and the batteries in this thing are dead.Instead of paying hundreds for new batterles can I just use a 110V to 24V transformer?Does it have to be 24 AC or 24 DC.Can I use another type of power supply that puts out 24 volts?Thanks for your input!!

author: BravoV
author_rank: Super Contributor
timestamp: January 12, 2019, 02:40:50 pm
content: The transformer you mentioned is mains connected, is this what you want that the wheelchair is constantly plugged at the electricity wall outlet ?A.k.a. your wheelchair is wired, not good for mobility.

author: Izzy
author_rank: Newbie
timestamp: January 12, 2019, 02:43:06 pm
content: Yes, I will want it plugged in!! Not concerned with having an extension cord run behind it!Also makes it a lot more compact!!!

author: wraper
author_rank: Unknown
timestamp: January 12, 2019, 02:52:55 pm
content: You need not a transformer but 24V SMPS (switch mode power supply). Transformer outputs AC but you need DC. Not to say even without rectifier, transformer will be larger, heavier and more expensive.

author: Zero999
author_rank: Super Contributor
timestamp: January 12, 2019, 02:53:47 pm
content: You certainly need DC, not AC. Fortunately 110VAC to 24V DC converters are widely available and aren't expensive.How many Amps does the motor draw? If you don't know, look at the nameplate on the motor and search the Internet for the part number, if it doesn't say.If it gives the power but not current, then it can be calculated using Ohm's law.You need a power supply which can deliver more current than the motor will use.

author: Izzy
author_rank: Newbie
timestamp: January 12, 2019, 03:55:49 pm
content: Thanks Zero999, can you give me an example?Ok I think it's the draw is 64 peak and 13 continuous.

author: soldar
author_rank: Super Contributor
timestamp: January 12, 2019, 04:56:52 pm
content: Some disjointed thoughts without proposing anything in particular.Electric cables around the floor are a trip hazard and an electric hazard.A motor will have a huge startup current compared to its continuous consumption. A battery can handle that pretty well but a power supply is going to have to be oversized.A DC motor would have high inductance and would not care much is the voltage is pure flat DC or pulsed in some way. You could probably use full wave rectified AC unfiltered. You could even use higher (mains) voltage with phase power control and full wave rectified. (Insert here all sorts of isolation, safety and security warnings.)

author: Zero999
author_rank: Super Contributor
timestamp: January 12, 2019, 09:03:49 pm
content: Quote from: Izzy on January 12, 2019, 03:55:49 pm13A at 24V is no problem. The peak requirement is a little more tricky though. A 24V power supply capable of 63A is going to be expensive.How are you going to control the speed of the motor?

author: exe
author_rank: Unknown
timestamp: January 13, 2019, 12:31:19 am
content: Quote from: Zero999 on January 12, 2019, 09:03:49 pmCan capacitors help with this? (though they won't be small)

author: spec
author_rank: Frequent Contributor
timestamp: January 13, 2019, 04:42:53 am
content: Hi IzzyThere are a heap of mains to 24V power supplies here:https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20190112202104&SearchText=24V+power+supplyJust search through the suppliers lists. You should get a 24V 60A power supply for around $75 US delivered. Remember that if you want to, you can put one or more power supplies in parallel.

author: james_s
author_rank: Super Contributor
timestamp: January 13, 2019, 06:35:29 am
content: Power supplies are dirt cheap. The power supply I use for some of my chargers for RC aircraft batteries supplies 24V at 54A and cost me $22. I used a pair of IBM server PSUs with a small modification to separate the DC ground from earth ground on one of them so they can be wired in series. I've been using it for years now, these are very commonly used by RC modelers. The power supplies are dirt cheap on the surplus market.