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Author Topic: Will an HO transformer burn up my 4-6-0 big Hauler  (Read 4758 times)
ajzend

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« on: January 19, 2010, 02:51:01 PM »

This is probably an old topic, but I'm new to G scale stuff.  The transformer that came with this 3rd generation big hauler is quite anemic.  I got out an old HO transformer, and it gives it a fair amount of umph.  It's not about to fly off the track, but it gets up to a descent speed and smokes descently with two passenger cars.  Will this burn up my motor?  Is there any advantage or problem in using the "pulse" feature?
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Joe Satnik


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« Reply #1 on: January 19, 2010, 03:42:59 PM »

Dear ajzend,

Get a voltmeter and tell us the full speed DC voltage at the power pack, with loco off rails,  then with loco on the rails. 

(Careful not to fly off the curves.)

Sincerely,

Joe Satnik 
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If your loco is too heavy to lift, you'd better be able to ride in, on or behind it.
Chuck N

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« Reply #2 on: January 19, 2010, 05:55:30 PM »

If anything is over taxed in your setup it will be the power supply.  My guess is that the top voltage on your HO power supply is significantly lower than the 20 to 24 volts a typical G gauge power supply puts out.  After running for a while, feel the engine and the power supply to see if one or the other is warm or hot.  In the absence of a volt meter this will give you a hint as to where the weak link is located. 

As Joe says, get yourself a volt meter.  They are very useful in studying problems such as this.  They aren't expensive.  You can get a good one for less than $30 at RadioShack. 

Chuck
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on30gn15


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« Reply #3 on: January 19, 2010, 07:22:01 PM »

On the pulse, it depends on several things.
On my MRC packs, of which a couple are rated for HO to G, the pulse helps smooth out low-voltage, low-speed, running, such as  freight car switching speeds. 

Have been told when I asked Hartland Locomotive Works why their literature said not to use pulse, that the alternating lower/higher pulses will tend to heat up the motor -  which in a motor sealed into a pretty much waterproof motor block would eventually be damaging.

Big Haulers aren't exactly "vacuum packed for freshness", so I'm not worrying about it since mine aren't usually run at jump off and pick a couple daisies speed.

NOW: what may cause trouble is leaving Big Hauler stopped on track with Bachmann power supply plugged in - all my Bachmann power supplies were still putting out 1 volt to 1.5 volts at "O" on speed control.

Unplug power if leaving train parked for any length of time.
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When all esle fials, go run trains
Screw the Rivets, I'm building for Atmosphere!
later, Forrest
ajzend

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« Reply #4 on: January 20, 2010, 12:34:32 AM »

Dear ajzend,

Get a voltmeter and tell us the full speed DC voltage at the power pack, with loco off rails,  then with loco on the rails. 

(Careful not to fly off the curves.)

Sincerely,

Joe Satnik 
I don't want to seem lazy, but I'm not sure that I even want to test the Bachmann power pack since I have to whack it to get the train to keep moving.  The engines moves very nicely with my MRC TechII Railmaster 2400.  Do I need to check the track voltage with this?  Is there a max voltage that I should not exceed. From one of the postings here it seems that a G transformer has more voltage than an HO transformer.  To put it simply; am I worrying too much about nothing?
Thanks,
Alan
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on30gn15


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« Reply #5 on: January 20, 2010, 08:40:07 AM »

Given most model train motor/voltage 2-rail DC powered combinations these days fall within a reasonably common zone it's most likely you'll be having Talladega style crashes in turn 3 before an HO transformer burns up a Big Hauler motor due to excess voltage.

Unless there's this irresistible urge to use your Big Hauler to pull pallets of bricks, or more than 3 or 4 passenger cars uphill all day, expect its motor to have a happy lifetime.
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When all esle fials, go run trains
Screw the Rivets, I'm building for Atmosphere!
later, Forrest
Jim Banner

Enjoying electric model railroading since 1950.


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« Reply #6 on: January 20, 2010, 07:48:52 PM »

A third generation Big Hauler running on 24 volts will pull a very long train for a very short time.  The problem is the motor.  Buried deep inside the locomotive where no air can circulate, it stifles in its own heat.  The metal motor mounting bracket in the later Big Haulers works as a heat sink and is a partial solution to the problem.  A better solution is to add a cooling fan.  A 2-1/4 inch microprocessor fan from an old computer can be fitted inside the smoke box, just behind the smoke stack.  The fan can draw cool air down the smoke stack and through some holes drilled out of sight through the bottom of the smoke box.  Then it can blow that cool air through the boiler and down around the motor.  A few more holes at the rear bottom of the frame under the cab can let the hot air out.  The best solution, as discussed earlier, is a BBT upgrade chassis.

An H0 power pack putting out 12 volts under load is very unlikely to burn up the motor in any Big Hauler except the first, radio controlled, version which had a small, 9 volt motor.

Jim 
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Growing older is mandatory but growing up is optional.
ajzend

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« Reply #7 on: January 22, 2010, 11:58:52 AM »

When I strapped down the motor to stop gear slippage it was to the metal weight above it.  Wouldn't this act as a heat sink?  Also, when doing that home grown upgrade (thanks to members of this forum) I did notice that the motor did have holes in its casing.  In any event, I'll avoid pulling pallet boards of junked Big Haulers.
I thank everyone for their help on this topic.
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doug c

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« Reply #8 on: January 24, 2010, 07:28:38 PM »

Newbies;

Even though LGB supplied a transformer in their starter kits, and some would presume it G sized  it does NOT power a loco like  SD-45  even as hooked up to my small indoor layout (my outdoor has a discontined PH-G' transformer).      Another reason/example of needing to know the size/number of motors in each loco' a person is thinking of using on their layout  . . . most cases beyond the engine supplied we have to upgrade our power supplies.

doug c
« Last Edit: January 25, 2010, 06:31:51 PM by doug c » Logged
Chuck N

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« Reply #9 on: January 24, 2010, 09:05:43 PM »

Doug:

Not only to mention an added a car with lights or and engine with smoke.  Starter set transformers are are just that.  Anything beyond a single motor, with lights, will tax the power supply.  Tight curves (R1), smoke, lights, and a few additional cars and you need a new power supply.

Chuck
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Doneldon

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« Reply #10 on: February 06, 2010, 01:19:19 AM »

You can get inexpensive electronics ventilation fans in just about any size at Radio Shack. 

With due respect to Jim Bannister, the Wizard of Wizards in the model train world, I would suggest using the fan to draw air around the motor and up the stack rather than down the stack and to the motor.  Pulling the air through will be a little more effective, the way a window fan is more effective when used to exhaust air than to pull air in.  Too, moving warm air from lower to higher is easier because that's what the warm air wants to do.  Reversing the fan means working against the normal air convection. 
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CoFrank

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« Reply #11 on: February 06, 2010, 08:01:52 PM »

I use an MRC Controlmaster II HO powerpack to run an Annie 4-6-0 and a 45-Ton diesel all at the same time. The 3 motors draw less than 1 amp at 10 volts and run at a reasonable speed. The powerpack is good for something like 20+ watts - plenty to run the above for hours at a time.
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