JJ73 Posted Saturday at 23:28 Share Posted Saturday at 23:28 Hiya I've got a bit stuck - on my You Tube Channel - I have a Video Called "H & M Power Controllers - Old & New, A Good Review" & Some one has started to ask me this Question - "what is the minimal voltage for the start could provide those controllers in half wave and high resistant mode for start?" Then I said "Sorry I have no clue - try Google!!" Then they said "do you really believe in Google in that thing? Even if fabrics do not telling the real data? Actually they use trick - 0...14. But 0 is not starting point. Only one fabric used to write true - 1.5-14V, it was Titan, but late versions only. Do you have multimeter?" Then I said "Oh ok - not sure if I 'believe in Google' - haven't really thought about it t. b. h. Did think about a multimeter, might have 1 somewhere, but not too sure about how to use it thou..." Then they said "for sure nice joke, but you are so experienced modeller that I believe you could teach how to do it many other colleagues I would be very happy if you measure it." & now I don't know how to reply because - Yes I do have a multimeter but never really understood how to use it - could any one please help me out in the next reply - what do I say??? Thanks in advance 🤔🚂 Link to comment Share on other sites More sharing options...
What About The Bee Posted Sunday at 00:22 Share Posted Sunday at 00:22 I will head on over to your channel JJ, so as to understand the individual better Bee Link to comment Share on other sites More sharing options...
What About The Bee Posted Sunday at 00:35 Share Posted Sunday at 00:35 I've had a look at his channel JJ. He appears to be a non-native English speaker. This will make for difficult communication. He is very clearly an intelligent fellow, and his experiments on video are thoughtful. He appears to be looking for the minimum voltage the controller produces. I asked him "Hello Alex. To clarify, you want the minimum voltage across the terminals, with nothing connected, at half wave?" Check to see if my question is there please. youTube has been deleting my comments of late, apparently I talk too much hahahaha Once he responds, I can help you to answer his question, and help you to understand a multi meter. Please take a picture of your multimeter, front and back, and post them here so I can tell you the exact settings. Bee Link to comment Share on other sites More sharing options...
JJ73 Posted Sunday at 22:18 Author Share Posted Sunday at 22:18 Hello Bee 1) Thank you for your help & 2) Yes, I see your replies & here are the photos of my multimeter... Link to comment Share on other sites More sharing options...
ntpntpntp Posted Sunday at 22:33 Share Posted Sunday at 22:33 (edited) I seem to recall the Low Resistance mode simply shorts out / bypasses part of the resistance mat behind the rotary knob. Half Wave does what it says - blocks half the rectified AC so you get a very crude form of fixed width pulsed power (so not like PWM). Half-Wave results in a lot of graunchy noise from the motor; modern coreless motors will hate it and may be fried by it. These features were useful with ancient 1950s O gauge models and Hornby Dublo which drew a lot of current, but for more modern 00, TT, and N mechanisms always leave the Duette set to High Resistance and Full Wave. I ripped out the resistance mats of my old H&M units more than 20 years ago and fitted simple Gaugemaster panel mount controllers in the cases. In this guise they're still useful controllers. Edited Sunday at 22:34 by ntpntpntp Link to comment Share on other sites More sharing options...
JJ73 Posted Monday at 01:10 Author Share Posted Monday at 01:10 Ok Thanks ntp Link to comment Share on other sites More sharing options...
What About The Bee Posted Monday at 04:56 Share Posted Monday at 04:56 After a bit of conversation with the gentleman, he just wants to know the dc voltage across the rails when your locomotive just sets out in motion. I pointed out that this is more a measure of your track and the locomotive you select and not really a good measurement of the controller. So many variables. He agrees He wants very slow constant motion. Set the slider bar to the second from the left. That is the V with the straight bar over it, meaning DC. The V with the wiggle line is for AC, like the voltage in your wall. The third from left is amperage while the fourth from left is resistance. The up and down slider selects the range of the measurement. So you would set it for the second one from the top, or 20 volts, because we expect your controller produces less than 20 DC volts. If you are unsure of what I said, set it and post a picture. I will help you to get the correct setting. Make sure you put a battery in the voltmeter!! Touch the red probe to one rail, the black to the other rail. The number you see in the display is the DC volts. Run a train, and measure the rails at different speeds. Your guy wants to know the voltage when it just starts out. Determine the controller setting that causes motion to start. Then measure like I told you. You can do this JJ. Bee 1 Link to comment Share on other sites More sharing options...
96RAF Posted Monday at 08:03 Share Posted Monday at 08:03 JJ - you may have seen recommendations to measure motor stall current using a multi-meter, but be aware that your meter is not suitable for that job as it has a 200mA limit on DC and if you tried to meter the motor stall amps you will blow the meter fuse if it has one. I agree with Bee that the respondent is not a native english speaker and that he is trying to find out what the lowest voltage is the controller will provide. The method Bee gives will show you when your loco moves to give you an idea, but each loco is going to be slightly different and it may be the controller will provide say around 1.5v minimum and not a smooth 0v incrementing upward. You will prove that with your meter. Link to comment Share on other sites More sharing options...
JJ73 Posted Tuesday at 00:13 Author Share Posted Tuesday at 00:13 Thanks Bee & Raf - Had a go - nothing went bang - so far - got no idea what I am doing - just showing me a load of Random numbers to me!!! I might do a quick video about this!!! Link to comment Share on other sites More sharing options...
What About The Bee Posted Tuesday at 00:40 Share Posted Tuesday at 00:40 The top photo shows 15.88 Volts, direct current (VDC). The bottom photo shows 14.84 VDC. Well done JJ. Now, do you have a locomotive on the track? Slow it right down JJ, then see the reading. It may be as low as 2 VDC. The voltage is related to speed. The higher the voltage, the higher the speed. The lower the voltage, the lower the speed. You are getting there! Bee Link to comment Share on other sites More sharing options...
What About The Bee Posted Tuesday at 00:42 Share Posted Tuesday at 00:42 About the negative / positive. This is polarity. Forward / reverse! This is just a fine point. Right now, we only care how big the number is, not the sign Bee Link to comment Share on other sites More sharing options...
JJ73 Posted Tuesday at 02:26 Author Share Posted Tuesday at 02:26 A quick chart... Loco Wheel Fig. Highest VDC Queen Maud 4-6-2 18 / 19 BR Black Tank Loco 0-6-0 18 / 19 Joyous Gard 4-6-0 19 / 20 Coca Cola 0-4-0 18 / 19 This was using the H&M Duette - I did kept on switching the Wave / Resistance back & forth & found the VDC numbers kept on going up & down, also I found that the VDC number has higher when there was NO Loco on the track about 24 VDC!!! 1 Link to comment Share on other sites More sharing options...
What About The Bee Posted Tuesday at 02:54 Share Posted Tuesday at 02:54 JJ What is the lowest VDC you get, with the locomotive still moving? That is what your question on youTube is Bee Link to comment Share on other sites More sharing options...
96RAF Posted Tuesday at 07:38 Share Posted Tuesday at 07:38 JJ - put the loco on track and watch to see what the reading is as you turn the speed up just enough to get the loco rolling. Do this fwd and rev as some locos are 'stiffer' in one direction than the other. Link to comment Share on other sites More sharing options...
JJ73 Posted Tuesday at 13:10 Author Share Posted Tuesday at 13:10 ok Link to comment Share on other sites More sharing options...
JJ73 Posted Tuesday at 13:16 Author Share Posted Tuesday at 13:16 So he want to know the lowest - (minus) number then??? Link to comment Share on other sites More sharing options...
96RAF Posted Tuesday at 13:22 Share Posted Tuesday at 13:22 5 minutes ago, JJ73 said: So he want to know the lowest - (minus) number then??? A minus number just indicates the direction has been reversed. The figure is the important bit, not the +/- status. Turn the speed knob down to off. Put the loco on track. Turn the knob slowly until the loco just moves and note the reading. If you reverse direction the value may vary depending upon the condition of the loco motor and gear train. 1 Link to comment Share on other sites More sharing options...
JJ73 Posted Tuesday at 14:09 Author Share Posted Tuesday at 14:09 A quick chart (slow this time) ... Loco Wheel Fig. Lowest VDC - Fwd / Back Queen Maud 4-6-2 1.8 / 1.4 BR Black Tank Loco 0-6-0 1.0 / 1.3 Joyous Gard 4-6-0 1.6 / 1.3 Coca Cola 0-4-0 2.3 / 1.8 Finally - I hope this will answer his question!!! 2 Link to comment Share on other sites More sharing options...
ntpntpntp Posted Tuesday at 14:25 Share Posted Tuesday at 14:25 Those figures look reasonable. If the person really wants good slow running of modern locos then he'd be better off with a more modern controller. Being a simple resistance-mat based controller the Duette is very susceptible to the resistance/inductance/load of the loco's motor. A modern plain DC electronic controller will be more consistent with its voltage output. PWM-based controllers are really good for slow running as long as the motor is not upset by the pulse frequency (some coreless motors aren't happy with low frequency PWM). DCC Decoders use PWM and achieve excellent slow running, they can use higher frequency PWM where appropriate. Link to comment Share on other sites More sharing options...
JJ73 Posted Tuesday at 14:26 Author Share Posted Tuesday at 14:26 Thank you ntp 😊 Link to comment Share on other sites More sharing options...
What About The Bee Posted Tuesday at 14:30 Share Posted Tuesday at 14:30 Good job JJ. I knew you could do it. Bee Link to comment Share on other sites More sharing options...
JJ73 Posted Tuesday at 14:39 Author Share Posted Tuesday at 14:39 Arrr that's sweet of you to say that Bee - Thanks Bee 😊🚂 1 Link to comment Share on other sites More sharing options...
Going Spare Posted Tuesday at 15:17 Share Posted Tuesday at 15:17 It is interesting to me to see that the smallest, lightest loco of the four run needed the highest voltage, by a good margin. Is this a characteristic of the Scalextric 'Pocket Rocket' can motor, to produce very high r.p.m. at full throttle? Link to comment Share on other sites More sharing options...
JJ73 Posted Tuesday at 17:15 Author Share Posted Tuesday at 17:15 Just to let you know (I hope that this is ok) I'm going to Name Check Bee, Raf & ntpntpntp on my Video for helping me out!!! 😊🚂 3 Link to comment Share on other sites More sharing options...
RB51 Posted Tuesday at 17:58 Share Posted Tuesday at 17:58 Nice touch JJ. R- Link to comment Share on other sites More sharing options...
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