Old Buffer
Western Thunderer
Looking very good and the action proved how good the mods are, also you did a great job of not spilling the beer.
Alan
Alan
Pugsley
Western Thunderer
Thanks again for the kind words everyone.
Alan - Couldn't spill the drink, that would be sacrilege! (It's not beer though - it's homebrewed cider)
Steve - It's going to be 37415, in IC Mainline livery, pretty much the same as in this photo:
http://www.flickr.com/photos/dmc1947/5759297151/sizes/l/in/photostream/
Complete with Thornaby Kingfisher, although it was a Tinsley loco by that point.
Alan - Couldn't spill the drink, that would be sacrilege! (It's not beer though - it's homebrewed cider)
Steve - It's going to be 37415, in IC Mainline livery, pretty much the same as in this photo:
http://www.flickr.com/photos/dmc1947/5759297151/sizes/l/in/photostream/
Complete with Thornaby Kingfisher, although it was a Tinsley loco by that point.
40126
Western Thunderer
Dog Star
Western Thunderer
I appreciate that this is cart/horse/bolt etc... why not consider making the axle with a telescopic joint and a taper pin to retain thereby allowing the wheels to be set back-to-back accurately before the traction motor is hung from the axle. OK, choosing the position for the taper pin might be interesting....
I ask because I am considering how to add traction motors to a wagon bogie and B2B will need to be accurate.
regards, Graham
Apologies, just realised that Cynric has asked the question.... and that you have replied.
Eastsidepilot
Western Thunderer
Looking forward to seeing this run Pugs, excellent work mate.
Col.
Col.
Pugsley
Western Thunderer
Thanks everyone 
Graham - I didn't do that as I considered it beyond my skills at the time. In the end, I went for solid axles and pressing the wheels on, time will tell if that really was the right option. If I were to do this again, I'd probably use the Roxey wheels, which have one insulated wheel pressed on, and the other that screws up against a shoulder to set the correct back-to-back. They also use a thinner axle, so I wouldn't use the Slaters hornblocks and wouldn't have to ream the gears out so far. In short, it would solve a lot of the problems I had.
Graham - I didn't do that as I considered it beyond my skills at the time. In the end, I went for solid axles and pressing the wheels on, time will tell if that really was the right option. If I were to do this again, I'd probably use the Roxey wheels, which have one insulated wheel pressed on, and the other that screws up against a shoulder to set the correct back-to-back. They also use a thinner axle, so I wouldn't use the Slaters hornblocks and wouldn't have to ream the gears out so far. In short, it would solve a lot of the problems I had.
Pugsley
Western Thunderer
Nothing as yet - I haven't quite made my mind up whether to do it or not. I don't think I'll have enough functions left on the decoder to have it switchable after doing the lighting - I was going for all lights independent, plus cab lights and I think the Zimo chip only has 8 functions. I guess I could add a second decoder to run it if I decide that's what I want to do.
Dog Star
Western Thunderer
Thank you for this reply. Just so that I have got the idea correct, how are you mapping the functions of the chip to the behaviour of the different features of the engine?
Thank you, Graham
Pugsley
Western Thunderer
The motors on each bogie are connected in series and the two bogies will be connected in parallel. I'm hoping that the chip will be able to cope with this arrangement, though I think I might have to disable the back EMF compensation.
The lights will be mapped to the 8 non-sound functions on the Zimo chip, with independant head/marker/tail/cab light at each end. I'm not sure how yet, as I've yet to procure the chip, but it shouldn't be too difficult. If I were to go for a second chip to drive the fan, I'd use a standard chip aimed at 4mm scale and run the motor from the decoder output, using a different chip address.
The main chip would be allocated 3715 and the second one 3716.
The lights will be mapped to the 8 non-sound functions on the Zimo chip, with independant head/marker/tail/cab light at each end. I'm not sure how yet, as I've yet to procure the chip, but it shouldn't be too difficult. If I were to go for a second chip to drive the fan, I'd use a standard chip aimed at 4mm scale and run the motor from the decoder output, using a different chip address.
The main chip would be allocated 3715 and the second one 3716.
S
Simon Dunkley
Guest
A thought, Martin, but you could fit a very low current motor directly driving the fan, and have it powered as a bypass to a "shunted" bridge rectifier (used as a constant brightness circuit) from the motor supply: as soon as you exceed 1.4v, the fan will rotate (at a constant speed and direction) and as soon as you reduce the supply, it will slow to a stop.
An alternative might be the circuit on this link, here.
Dog Star
Western Thunderer
My original question....
And the reply....
Anyone else made a cooling fan operate?
In passing...
What determines the fan speed in the prototype Cl37... engine speed? coolant temperature? a combination of both?
and...
When might the engine be running and the fan stationary? and vice-versa?
thank you, Graham
And the reply....
Anyone else made a cooling fan operate?
In passing...
What determines the fan speed in the prototype Cl37... engine speed? coolant temperature? a combination of both?
and...
When might the engine be running and the fan stationary? and vice-versa?
thank you, Graham
Old Buffer
Western Thunderer
Graham,
I have seen on rmweb a few posts showing cooling fans working, can't remember which ones. As I am not into DCC I personaly can't help, but I think Brian Daniels may have the answer you desire.
Alan
Pugsley
Western Thunderer
As far as I'm aware, depending on the particular loco class, it's purely down to coolant temperature. So there will be times when the engine is colder than the fan activation temperature, for instance after starting, where the engine is running and the fan isn't turning. Likewise, there will be times where the cooling system has reduced the coolant temperature below the point the fan is switched on when the engine is under light loading.
Under heavy loads the cooling system will struggle to reduce the coolant temperature below the fan activation temperature, so it will run constantly. There are also moving shutters involved as well, obvious on the class 50's, but also present on the 37's AFAIK. The Class 50's have an electrically driven fan, which has two speeds selected automatically depending on coolant temperature, but the refurbished 37's had a mechanical drive controlled by an electro-magnetic clutch linked to the coolant temperature, so probably only one speed.
Reading between the lines, it's possible that the fan rotates continuously on the unrefurbished 37's as it's driven mechanically from the engine.
HTH
Pugsley
Western Thunderer
Thanks for the suggestions, but I wanted something that I could control directly on or off, rather than working from track power automatically. I'd also be a bit wary of connecting an auxiliary motor to a DCC motor output like that, as I'd hate to blow up an expensive chip by getting it wrong!
What I need is a small diesel engine and a generator....
