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Using 3.7v motors (was Re: Blackstone K-27 Re-motor Kits)


Mick Moignard
 

The issue with using 3.7v motors is current draw.  Power = V*A, so if you reduce V, you have to increase A to get the same P, by a factor of a little over 3 (12 divided by 3.7).  Or put it another way, these 3.7v motors aren't powerful enough to run model locos.   And if they were, they'd be the same size as the current 12v motors, so you'd have no real saving of space.  

I'd also be interested to see how such a decoder could reduce the track voltage from 14v or so to 3.7v, and still pass 2A or so or so the 3.7v motor without generating a lot of excess heat.  

Mick

______________________________________________________________________
Mick Moignard
Specialising in DCC Sound
p: +44 7774 652504
e:
mick@...
skype: mickmoignard
The week may start M,T but it always ends up WTF!


cmdrwmriker
 

Good points mick but you overlooked the S-cab operation. It is a 3.7vdc battery powered system. With a 3.7 Vidc decoder the dc to dc converter would be eliminated thus saving space. A battery powered loco does not need keep alive. Motor size does not play a big part in the system. I currently operate brass locos mod for S-cab 3 hours on a fully charged battery-no track power. The v.a in an S-cab system would be the same with or without a 3.7vdc decoder, well, until battery voltage began to decay. The li-ion batts have a relatively flat discharge rate.

----- Original Message -----
From: Mick Moignard <mick@...>
To: HOn3@groups.io
Sent: Mon, 07 Sep 2020 03:40:14 -0400 (EDT)
Subject: [HOn3] Using 3.7v motors (was Re: Blackstone K-27 Re-motor Kits)

The issue with using 3.7v motors is current draw. Power = V*A, so if you
reduce V, you have to increase A to get the same P, by a factor of a
little over 3 (12 divided by 3.7). Or put it another way, these 3.7v
motors aren't powerful enough to run model locos. And if they were,
they'd be the same size as the current 12v motors, so you'd have no real
saving of space.

I'd also be interested to see how such a decoder could reduce the track
voltage from 14v or so to 3.7v, and still pass 2A or so or so the 3.7v
motor without generating a lot of excess heat.

Mick

______________________________________________________________________
Mick Moignard
Specialising in DCC Sound
p: +44 7774 652504
e: mick@...
skype: mickmoignard
The week may start M,T but it always ends up WTF!


Mark Kasprowicz
 

Understand that the electronic components used in decoders are sourced from the cell phone industry and so operate at 3.7 volts. But the motors commonly used at present are a spin off from the automotive industry - hence the 12v standard. Also motor size matters in HOn3, the chances of fitting a decoder, receiver, speaker and a Li-ion battery inside an HOn3 C-16 are remote and we haven't even considered the much bigger n scale market.
I really love the concept but until some serious size shrinking takes place I'm afraid it's not for me.

Mark K


Alan
 

Don’t know for sure but I think the issue with a so called 3.7 v decoder is keeping the processor running. Seems to me they do not like going below 3.3 volts which means not much run time before the battery sags to that level ??????

 

Sent from Mail for Windows 10

 

From: cmdrwmriker
Sent: Monday, September 7, 2020 10:00 AM
To: HOn3@groups.io
Subject: Re: [HOn3] Using 3.7v motors (was Re: Blackstone K-27 Re-motor Kits)

 

Good points mick but you overlooked the S-cab operation. It is a 3.7vdc battery powered system. With a 3.7 Vidc decoder the dc to dc converter would be eliminated thus saving space. A battery powered loco does not need keep alive. Motor size does not play a big part in the system. I currently operate brass locos mod for S-cab 3 hours on a fully charged battery-no track power. The v.a in an S-cab system would be the same with or without a 3.7vdc decoder, well, until battery voltage began to decay. The li-ion batts have a relatively flat discharge rate.

----- Original Message -----

From: Mick Moignard <mick@...>

To: HOn3@groups.io

Sent: Mon, 07 Sep 2020 03:40:14 -0400 (EDT)

Subject: [HOn3] Using 3.7v motors (was Re: Blackstone K-27 Re-motor Kits)

 

The issue with using 3.7v motors is current draw.  Power = V*A, so if you

reduce V, you have to increase A to get the same P, by a factor of a

little over 3 (12 divided by 3.7).  Or put it another way, these 3.7v

motors aren't powerful enough to run model locos.   And if they were,

they'd be the same size as the current 12v motors, so you'd have no real

saving of space.

 

I'd also be interested to see how such a decoder could reduce the track

voltage from 14v or so to 3.7v, and still pass 2A or so or so the 3.7v

motor without generating a lot of excess heat.

 

Mick

 

______________________________________________________________________

Mick Moignard

Specialising in DCC Sound

p: +44 7774 652504

e: mick@...

skype: mickmoignard

The week may start M,T but it always ends up WTF!