Any components/electonic design that makes wire swaping ?! - Page 1
Forum section: electronics / projects

author: CyberWalker
author_rank: Contributor
timestamp: August 05, 2013, 05:37:40 pm
content: Hello to everyone!I would like to make a brushless motor turn either closswise or anti-closewise. This can be done by swaping any 2 of the 3 wires that feed it with AC current (from the speed control).I do not know any speed control that can run my motors (22.2 V, 40A continuous) with the selection of invertsign the rotation direction, so I decided to make a small wire-swaping project.The thing is that can be easily done with relays but the relays are heavy and consume energy (on their coil) so I am searcging to do this with MOSFETs (or solid state relays) but the ones I find are very expensive, although the actual MOSFETs used are cheap.Does anyone happen to have any idea about this? Has anybody tried sth similar before? Thak you very very much.Bellow you can see my idea about the mechanical relay and how could it swap wires 1 and 2. This is what I would prefer to do with solid state (cheap) components on a board.1 2 3| | ||* * |/ / ||- - - - /- - - - - - - - - / |/ / |* * * * ||| |_______| | || | | || 2 | ||_____________| || 31Thank you very much!! :-)

author: c4757p
author_rank: Super Contributor
timestamp: August 05, 2013, 05:39:59 pm
content: You're worried about relay coil power consumption when your motor takes 40A?

author: CyberWalker
author_rank: Contributor
timestamp: August 05, 2013, 05:44:26 pm
content: Yes I know, but it happens to be a big problem here. The driving circuits have a different battery, the ICs sink is not high enough (to hold a lot of milliamps), the designs has to be as simple as possible and the 40A are going to be applied for 10 seconds but the milliAmps on the coil for 5 hours the least. So the solid state design becomes important for all these reasons.

author: Galaxyrise
author_rank: Frequent Contributor
timestamp: August 05, 2013, 05:52:34 pm
content: Quote from: CyberWalker on August 05, 2013, 05:44:26 pmNot all relays require the coil stay energized. Would a latching relay work for you?

author: CyberWalker
author_rank: Contributor
timestamp: August 05, 2013, 06:02:20 pm
content: Yes it would. I searched for some latching relays but I only found expensive and quite heavy ones.If they are cheap then the weight can be neglected... But still I prefer cheap and light if there is such an option.Do you happen to have anything particulary appropriate in mind?

author: IanJ
author_rank: Unknown
timestamp: August 05, 2013, 06:18:23 pm
content: Hi,If I were you I wouldn't switch the motor wires, but rather look at the control system and do the switching there. Probably a lot easier and more reliable. Do you have the control system already.....post details.Ian.

author: CyberWalker
author_rank: Contributor
timestamp: August 05, 2013, 06:50:51 pm
content: Yes, that's a very nice idea!I will be using a commercial (end user) ESC so if you happen to know any ESC (electronic speed control) device that can be hackable (maybe to change the sequence of the steps) or even better one that supports this capability) then OFCOURSE I prefer this method! :-)* you can see a photo of a standard ESC here :http://en.wikipedia.org/wiki/Electronic_speed_control

author: cyr
author_rank: Frequent Contributor
timestamp: August 05, 2013, 07:53:10 pm
content: There are lots of hackable speed controllers, and at least two commonly used open source replacement firmware projects (both aimed at multirotors mainly).https://github.com/sim-/tgyhttps://code.google.com/p/wii-esc/Neither "officially" supports reversing AFAIK, but there are versions that do apparently:http://www.rcgroups.com/forums/showthread.php?t=1849952I have no idea if they would actually work for your application...