Salvaged motors with no markings - How to coerce information from them? - Page 1
Forum section: electronics / beginners

author: GiskardReventlov
author_rank: Frequent Contributor
timestamp: February 13, 2014, 11:42:15 pm
content: I have salvaged some motors from a tv/video combo and a dvd player and a sony video cam.I thought that I might be able to find out a little about them by connecting them to my DMM and spinning them to see what they output. Is this a valid, reliable method to determine their input?I was trying it on a servo and I got DC ~1.8 V but I still need to find the data on the servo as it's not marked.

author: poorchava
author_rank: Super Contributor
timestamp: February 14, 2014, 01:10:36 pm
content: Please post pictures.Motors in such stuff are most likely custom and you will not find any specs or datasheet.

author: GiskardReventlov
author_rank: Frequent Contributor
timestamp: February 14, 2014, 09:02:07 pm
content: Quote from: poorchava on February 14, 2014, 01:10:36 pmI will post some pictures, but my question is generic for any motor.

author: Greorge
author_rank: Regular Contributor
timestamp: February 17, 2014, 01:16:56 am
content: I would like to find out more about proper procedure too.What I do now is, I start with 1.2V rechargeable battery (which is about 1.3V when charged) and keep adding batteries until motor starts spinning.I understand that this is crude method, but I don’t have proper adjustable power supply.I am bit worried to use various power supplies, as not sure what will happen when power supply is 5V 300mA and unknown motor needs 1A or more.(I am worried that power supply might burn out - but not sure if my assumption is correct)EDIT: How can I subscribe to thread that I want to follow?

author: GiskardReventlov
author_rank: Frequent Contributor
timestamp: February 17, 2014, 06:56:25 am
content: Quote from: Greorge on February 17, 2014, 01:16:56 amNot a bad idea, I have been trying them out on a breadboard, your idea is safer for the motor.QuoteThere are two ways to setup notification. You can do that so every post you create or reply to will send you a notification when someone posts. Or at the top of each page next to "Reply" there's a notify button so you can be notified only on posts you select.

author: Greorge
author_rank: Regular Contributor
timestamp: February 17, 2014, 09:40:30 am
content: Quote from: GiskardReventlov on February 17, 2014, 06:56:25 amThank you for help.Excuse me asking one more question not related to thread subject.What do I do when I want to stop following particular therad?Do I press "Notify" button again?

author: sourcedog
author_rank: Newbie
timestamp: February 17, 2014, 09:46:59 am
content: Quote from: Greorge on February 17, 2014, 09:40:30 amExperimentation is the core of the scientific method. Just press and see what happens. You're not going to destroy the forums by doing that

author: GiskardReventlov
author_rank: Frequent Contributor
timestamp: February 17, 2014, 10:37:01 pm
content: Quote from: Greorge on February 17, 2014, 09:40:30 amIt's the Unnotify button if you've enabled notify.

author: electronics man
author_rank: Frequent Contributor
timestamp: February 17, 2014, 11:10:46 pm
content: connect it to a variable power supply whith a current limit set, then slowly ramp up the voltage until you get good speed this way you can find the voltage rating, but for torque and speed i have no idea.

author: Greorge
author_rank: Regular Contributor
timestamp: February 18, 2014, 12:13:48 am
content: QuoteThank you, appreciate your help.Up to 12V I add more 1.2 rechargeable batteries.For 12V I use spare car battery that is no longer good for car, but still good for small loads.As to power supply above 12V I have Laptop power supply 150W that can be adjusted from 15V to 24VFor voltage above 24V don’t have method.Until now didn’t have need for more than 24V either.Is it easy to make myself adjustable DC power supply, or better get one?Also what would be the best entry level ( = not expensive ) adjustable DC power supply?

author: kc9qvl
author_rank: Regular Contributor
timestamp: February 18, 2014, 02:09:02 am
content: To really tell you need some items.1 variable power supply or batteries.2 Current measurement could be part of power supplyNow you need some way of placing a load on the motor and measuring rpm.I recommend rc airplane propeller. Get a couple sizes. Say a 7x4 and a 10x4.7 Also a hub for the size of the motor shaft 3mm and 3.175 mm being common.Most of these propellors are well documented as to motor load (torque) per rpm at a static load. You would also need an optical tachometer to measure rpm. And maybe a thermometer to measure motor temperature.