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Discussion starter · #23 ·
Depends on exactly where you are making the measurements? There will be a drop, the key thing is not the size of the drop but how much does that drop vary with current. Remember also to measure at the terminals on the S-H board to remove any effect of volt drop in the cables which at high currents can be significant.

An important reminder that with higher numbers of cars and higher performance motors you will have to pay very close attention to power distribution with digital. All the cars are on the same lane and no point in having a good output stage if you then throw it all away in getting the power to the cars.

Measuring the drop with no load I see about 1 Volt drop, however with a 25 Amp load that drop only increases to 1.1 Volts, which is extremely good.
Image


Rich
 
I get a similar drop. I have an analog volt gauge measuring at the track rails and go by that, referencing the digital voltmeter on the power supply as well (it also shows current draw). Sure is a slick set up! Thanks again, Rich!
Doug
 
Here are a few minor tweeks and changes following further testing and feedback from Phil.



I have substituted the cables for terminal block, these fit nicely into a slot cut in the blue box. Also a mutiturn pot fitted to allow easier adjustment of the overload current.

I have used a 500 Ohm Pot in place of the 1K & reduced the series resistor from 120 to 100 Ohms. This allows setting of the current between 6 Amps & 35 Amps.



Here is a table showing approximate resistance V Overload level. This can be measured with a multimeter on the Jack plug before plugging into the Console, connect the multimeter between the two non-tip connections.

This enables you to set to a chosen current however I highly recommend going round the track and shorting the rails to ensure that the overload protection cuts in reliably. The Red & Green LED's will flash as long as a short is present as the unit briefly applies to power to see if the short has been removed.

If anyone else has built a unit I would be interested if these values seem accurate as it is very dependant on the circuitry in the Ninco Console. I do not know how close the tollerences are and only have one unit to test.



The removed piece of case from above the fan is stuck with circular double sided velcro to the top of the fan, which leaves a gap for the air to exit. These two units ready to send off to Phil later this week.

Rich
 
If you use the voltage divider to Enable SimpleH this way, you'll get aprox. 9 v on EA. The higher voltage admited to Enable it is about 5v, at higher voltages like this the S-H works but the mosfets long life couldn't be guaranteed.

I think it's better to enable SimpleH using this way:

1- Remove 1200 and 5600 ohm resistors.

2- Enable Straight using another wire from +5 v stabilized from Ninco PB to EA, then there will be 4 wires from Ninco PB to Simple-H but you're sure you always enabling correctly and in stable way. Not depending on the voltage of the third party power supply. To get +5v on Ninco PB (See picture).
Image
 
Are correct the resistor divisor values?

Total R = 1K2 + 5K6 = 6K8
14,2 Volts / 6800 Ohm = 2 mAmp
2 mAmp * 5K6 Ohm = 11,6 Volts to Enable-Pin

If resistor to V+ is 12 KOhms, and the resistor to ground is 5K6 Ohms:

Total R = 12K+ 5K6 = 17K6 Ohms
14,2V / 17K6 = 0,8 mAmps
0,8m Amps x 5K6 = 4,5 Volts to enable PIN

SIMPLE-H Manual:
2.5V - 5.5V = logic high
<1.7V = logic low
 
QUOTE (Txus @ 15 May 2011, 20:20) <{POST_SNAPBACK}>Are correct the resistor divisor values?

Total R = 1K2 + 5K6 = 6K8
14,2 Volts / 6800 Ohm = 2 mAmp
2 mAmp * 5K6 Ohm = 11,6 Volts to Enable-Pin

If resistor to V+ is 12 KOhms, and the resistor to ground is 5K6 Ohms:

Total R = 12K+ 5K6 = 17K6 Ohms
14,2V / 17K6 = 0,8 mAmps
0,8m Amps x 5K6 = 4,5 Volts to enable PIN

SIMPLE-H Manual:
2.5V - 5.5V = logic high
<1.7V = logic low

That's right.
 
Hi RichG
We are struggling to get our simple h mod to work
We have followed all the instructions here and there is no response on the power base

There is a pic that shows that we must lift the 1k resistor and then the next pic looks like it's been flattened back. That is the only thing we can see looks different. There must be something we have done wrong. Are any of the led's on the simple h supposed to light up and when?

Thank you

Geoff
 
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