Battery operated power drill chuck rotation opposite of intened direction - Page 1
Forum section: electronics / repair

author: videobruce
author_rank: Frequent Contributor
timestamp: September 28, 2017, 01:15:26 pm
content: This is a good one, especially since it involves the drill changing directions from one day to the next. (The motor assembly was changed out previously)Long story short:Bosch hand held drill chuck rotation was reverse what it should be. I opened the enclosure and reversed the motor leads and all was fine. I used it a number of times that same day. The very next day when I checked to confirm all was ok, it reverted back to opposite rotation by itself. Forward was reverse, etc.There are two transistors (3 leg) attached to the heat sink in the base of the handle and one other component (2 pin), rectangular in shape. My guess is it's a capacitor, but I never saw one like that before, the corners were not rounded. If there are any other components, they would be in the trigger switch itself.Ok, would someone like ti explain WTF is going on? I haven't tried to re-reverse the motor leads again yet.

author: SeanB
author_rank: Super Contributor
timestamp: September 28, 2017, 06:08:49 pm
content: You have a reversing switch and are randomly operating it. only real explanation, most electric drill now do have them.

author: videobruce
author_rank: Frequent Contributor
timestamp: September 29, 2017, 03:20:36 am
content: The switch isnot"randomly" being operated. I have used enough hand held tools to know how to operate them especially drills and more especially since I have a 2nd exact same model.

author: David_AVD
author_rank: Super Contributor
timestamp: September 29, 2017, 10:03:39 am
content: Are you the only one with access to the drill? ie Could someone be messing with your sanity?

author: xavier60
author_rank: Super Contributor
timestamp: September 29, 2017, 11:31:43 am
content: Usually with battery powered drills that have a brushed motor, any electronics in the drill are for PWM speed control only, not for reversing polarity to the motor. I wonder if there is something loose or slipping inside of the reversing switch causing it to sometimes reverse its action.

author: videobruce
author_rank: Frequent Contributor
timestamp: September 29, 2017, 01:02:55 pm
content: Yes, I'm the only one that uses it.The reverse switch is solid, no glitches, dead spots etc. It was suggested elsewhere that there is a microprocessor somewhere. If so, I'd like to know where it is. Like I said, I only see 3 components at the base of the handle just above where the battery pack is and nothing else.See this link;https://www.boschtoolsservice.com/Order/IPL/IPLDetails.aspx?tn=3601H66110&mn=DDS181-02&RelatedTools=3601H66110;%203601H66111;&init=1I contacted their support. The support guy I talked to says there is a microprocessor in or attached to the trigger switch. He didn't know what this large retangular component was. He had no idea why it did what it did either and will pass it up the chain.In the mean time, I will re-open it back up, swap leads again and see what happens (without closing it up again).

author: StillTrying
author_rank: Super Contributor
timestamp: September 29, 2017, 01:56:21 pm
content: Brushes moving/rotating around a bit?https://www.toomanytools.com/moteur-bosch/2000-bosch-moteur-a-courant-continu-18v-2609199359.html

author: videobruce
author_rank: Frequent Contributor
timestamp: September 29, 2017, 03:53:07 pm
content: Are you referring to 'slop'?Ok, there apparently is, or probably is a microprocessor, it's in a sealed (epoxy) circuit board at the very base just above the plate that holds the battery. I didn't notice it before, but I did now. It's surely isn't in the trigger. I swapped the leads, it runs correction for now.That mystery part on the heat sink # is 2109771077, but a search only turned up phone numbers.

author: AF6LJ
author_rank: Unknown
timestamp: September 29, 2017, 03:57:55 pm
content: I remember this discussion...

author: videobruce
author_rank: Frequent Contributor
timestamp: September 29, 2017, 05:18:13 pm
content: Details?Bosch did get back to me and suggested the 'plate' that has the brushes a possible problem. I have examined it and see or feel no exception. They told me to let them know of any developments which was refreshing for a change..

author: AF6LJ
author_rank: Unknown
timestamp: September 29, 2017, 05:24:47 pm
content: This was discussed yesterday over here...http://www.eham.net/ehamforum/smf/index.php/topic,116942.msg1023776.html#msg1023776

author: videobruce
author_rank: Frequent Contributor
timestamp: September 29, 2017, 05:48:31 pm
content: With no resolve either.

author: StillTrying
author_rank: Super Contributor
timestamp: September 29, 2017, 09:30:25 pm
content: You can get a close up view of the brushes on here, and here. But I don't know anything more about this type of DC motor. (or any other type come to think of it!)http://www.elektroserw.pl/product-pl-2770-Bosch-silnik-do-wkretarki-2609199359-GSR-18V-LI.htmlhttp://ctn.home.pl/pl/p/Silnik-wkretarki-Bosch-GSR-18-V-LI-.-GSB-18-V-LI-.-GSR-18-V-LI-HX-2/1391

author: xavier60
author_rank: Super Contributor
timestamp: September 30, 2017, 12:33:11 am
content: My Makita charger went from making beeping sounds to playing tunes because by chance I did a series of actions that changed a setting.I wonder if there is a sequence of actions that will toggle the action of the direction switch on the Bosch drill.

author: Cyberdragon
author_rank: Super Contributor
timestamp: September 30, 2017, 02:07:02 am
content: A DC motor requires an H-bridge to reverse, which is not possible with only 2 transistors. It's either in the motor or the gearing.

author: Nusa
author_rank: Super Contributor
timestamp: September 30, 2017, 02:26:00 am
content: If the reverse switch works, wouldn't simply changing that switch be a lot easier than swapping the motor leads? I know it doesn't explain the phenomenon, but it's eminently more practical than opening it up every time it goes the wrong way.

author: AF6LJ
author_rank: Unknown
timestamp: September 30, 2017, 03:09:57 am
content: Quote from: videobruce on September 29, 2017, 05:48:31 pmTruthfully; I wouldn't worry about it, just use the drill.

author: videobruce
author_rank: Frequent Contributor
timestamp: September 30, 2017, 04:33:56 pm
content: I did open it up again and swapped leads. Checked it twice afterwards before I buttoned it back up. Did so today, re-assembled it and used it. So far so good. If it happens again, yes I will just use it as remembering that the directions are reversed.

author: Cyberdragon
author_rank: Super Contributor
timestamp: September 30, 2017, 06:58:09 pm
content: I might be talking nonsense but is it ok to run a DC motor going in the wrong direction for the given polarity? (if it is the motor at fault)

author: AF6LJ
author_rank: Unknown
timestamp: September 30, 2017, 08:43:44 pm
content: Quote from: Cyberdragon on September 30, 2017, 06:58:09 pmIt won't hurt the motor to run it en ether direction.

author: Theobald
author_rank: Contributor
timestamp: October 02, 2017, 11:35:14 am
content: Following Cyberdragon: is it possible for a DC motor to start in the wrong way ?Interesting question, because the mechanical design is symetrical, if you want to make it turn in the both directions. I guess brushes vs magnets position is crucial.Any DC motor specialist on duty ?Theo

author: David_AVD
author_rank: Super Contributor
timestamp: October 02, 2017, 08:23:21 pm
content: Measuring the voltage polarity applied to the motor in the "normal" and "wacky" states would clear up whether it's the motor (unlikely) or electronics playing up.

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 03, 2017, 09:55:26 pm
content: Quote from: David_AVD on October 02, 2017, 08:23:21 pmThe electronics can't change the polarity with only two transistors unless they have three rails, plus, minus, and 0V. It might also be some oddity with the snubber causing a reverse pulse that starts it in the wrong direction.

author: David_AVD
author_rank: Super Contributor
timestamp: October 04, 2017, 09:00:31 am
content: OK then, how about "Measuring the voltage polarity applied to the motor in the "normal" and "wacky" states would clear up whether it's the motor (unlikely) or switch (including whatever circuitry) playing up."