mrpete222 Needs help with DC motor controller - Page 1
Forum section: electronics / beginners

author: Racer X
author_rank: Newbie
timestamp: March 29, 2015, 07:20:22 pm
content: The only thing I noticed was the loose pots for the field wires. Nothing else stood out to me in the video.Notes: The motor previously worked before being stored. The controller initially used failed, and so the motor was benched. With the new controller wired up seemingly correctly, there is still no output. Relay engages, 110V A/C in, but nothing out. Power on LED is illuminated.The rest is contained within the video.

author: SeanB
author_rank: Super Contributor
timestamp: March 29, 2015, 07:30:40 pm
content: I will guess the controller is actually working, but is not being enabled properly, or is being held in an emergency stop state by an open circuit input. S4 looks like it might perform that function, as many DC controls ( and variable speed AC drives) need a shorted link before they do anything other than sit there with power applied.

author: Racer X
author_rank: Newbie
timestamp: March 29, 2015, 07:51:34 pm
content: Gotcha! I'll pass that along.

author: Andy Watson
author_rank: Super Contributor
timestamp: March 29, 2015, 08:07:23 pm
content: Any idea what value potentiometer is being used ?

author: Racer X
author_rank: Newbie
timestamp: March 29, 2015, 08:10:36 pm
content: Only way to know is to ask the YouTuber.

author: oldway
author_rank: Super Contributor
timestamp: March 29, 2015, 08:21:02 pm
content: The potentiometer must be a 5K value but I am sure that's right.http://www.manualsdir.com/manuals/350810/kb-electronics-kbcc-225r-kbcc-125r-kbcc-225-kbcc-125.html?page=14APPLICATION INFORMATION: A INHIBIT:All models contain Terminals I1 and I2 that provide an INHIBIT function which electronically extinguishes the output of the control. This circuit is activated by connecting the I1 and I2 terminals togetherI did not find those terminals on your drive.I don't understand why.

author: Racer X
author_rank: Newbie
timestamp: March 29, 2015, 08:30:52 pm
content: Thanks! I have passed that along as well.

author: Sirius631
author_rank: Contributor
timestamp: March 29, 2015, 10:21:55 pm
content: Quote from: oldway on March 29, 2015, 08:21:02 pmThe inhibit lines still exist, just not on the terminal block. They are on the PCB and must be disconnected.http://spectechind.com/Documents/KB/kbpb125-manual.pdf

author: Racer X
author_rank: Newbie
timestamp: March 30, 2015, 12:18:49 am
content: Must be disconnected?

author: Sirius631
author_rank: Contributor
timestamp: March 30, 2015, 04:43:05 am
content: Quote from: Racer X on March 30, 2015, 12:18:49 amThey are inhibit lines, not enable lines. Join them and it inhibits the operation. As per the diagram, you could connect them to a switch, but that switch needs to be open for the drive to run, otherwise you are permanently coasting to a stop, and where does coasting to a stop get you when you are already stopped?

author: oldway
author_rank: Super Contributor
timestamp: March 30, 2015, 08:31:24 am
content: You should have a field voltage as soon as you plug in the mains.The only fuse is the line fuse.There is no switch or relay to cut off the field and it is a simple diode bridge.Check why you do not have a field voltage between F+ and F-.

author: oldway
author_rank: Super Contributor
timestamp: March 30, 2015, 09:49:31 am
content: I think what happened is simple to understand.You probably made a mistake at the first connection.You should have connected the armature on the output F + and F-.You switched on the mains voltage without checking first your connections.You had to check first the resistance between:A1 and A2: you have to find a very low resistance, on the order of a few ohms.F + and F-: resistance should be about 165 ohms.As there is no fuse for field protection, when you have switch mains on, one of the tracks of the printed board (field circuit) served as a fuse and is now blowned off.What you need to do:- Check all diodes to check they are not shorted- Repair the print board with a jumper.

author: Sirius631
author_rank: Contributor
timestamp: March 31, 2015, 11:13:06 am
content: Quote from: oldway on March 30, 2015, 08:31:24 amWon't the field voltage be suppressed by the controller if the inhibit lines are engaged? I believe that presence of a field voltage would cause the motor to brake, rather than coasting to a stop, as described in the datasheet.Older versions of the controller have I1 & I2 on the connector strip. From what I can see, these connection will be on the reverse side of the controller PCB used by mrpete222.OP, any progress on this?

author: oldway
author_rank: Super Contributor
timestamp: March 31, 2015, 02:27:49 pm
content: QuoteNo, look at the schematic, there is nothing to switch the field off.Only a bridge rectifier from the main supply.Braking is made by a brake armature resistor (R22A - R22B on APRM schematic) switched on by a thyristor SCR1.SCR1 turn off when armature current is under holding current of the SCR.

author: Sirius631
author_rank: Contributor
timestamp: March 31, 2015, 04:16:31 pm
content: Quote from: oldway on March 31, 2015, 02:27:49 pmDo you mean the schematic shown in the video, as drawn by another of mrpete222's contacts? That schematic cannot be accurate as it doesn't show anything relating to the inhibit lines? Must confess, I've not looked in detail at any schematic in the up-to-date datasheet. I'll take a moment now to so do.

author: oldway
author_rank: Super Contributor
timestamp: March 31, 2015, 05:00:35 pm
content: Schematics are in the last pages of kbpb125-manual.pdf from your link...