Motors don't run at a constant voltage with command control.  AAMOF, the voltage the motor sees with command or conventional at the same speed should be pretty much the same voltage, think about it.   I seriously doubt the waveform has that much to do with how hot the motor gets.  The motor is a pretty large inductance and swamps out most issue with the non-sinusoidal waveform.  The analysis I've seen attributes at most a few percent energy loss over pure DC with a PWM drive.

gunrunnerjohn posted:

Motors don't run at a constant voltage with command control.  AAMOF, the voltage the motor sees with command or conventional at the same speed should be pretty much the same voltage, think about it.   I seriously doubt the waveform has that much to do with how hot the motor gets.  The motor is a pretty large inductance and swamps out most issue with the non-sinusoidal waveform.  The analysis I've seen attributes at most a few percent energy loss over pure DC with a PWM drive.

John

I know that. In command control, the motor voltage must be either chopped or PWM, I don't know which. So, I am suggesting that the wave form makes a difference. 

Keith

I have no issues with any motors getting unusually hot, and I do pretty much exclusive command.  I also have tons of locomotives on the bench testing at various times, and this has never been an issue.

The waveforms for command can be either PWM or the triac sawtooth wave, I don't see it making a difference.  Since I don't have any "hot" motors, it's hard to narrow it down.

I'm going to do a test with a Williams A-A set I have, they're stock from the factory, a set that I always intended to upgrade...  Since the contention is that the Williams motors get hot in conventional mode, that seems to be the most germane.

I apologize for not getting back here sooner. All testing done on an 031 oval with about 8 freight cars, all plastic with die-cast trucks/couplers. Transformer, etc changes make no difference.

FYI, one of my engines, that was "downgraded" from PS2 to a Dallee Reverse Board and Williams Sound Board also gets hot. I don't remember it getting how with PS2 but then again, I wasn't really paying attention to that then. The motors are original, MTH motors, One still even has the tach stripes and such on it. The loco is an F3 from 2004. It did have a Williams reverse board that also got very hot.

I purchased a NIB Williams GP9 from Mario's Trains a few months ago. It also got extremely hot after a short time in operation on an 031 oval. That went back to Mario.

My Williams Bachmann J also gets very hot, waiting on a new motor as a possible option.

My original Williams SD90 also gets hot although it doesn't seem to get AS hot as the rest.

I notice my el-cheapo but incredibly durable and reliable Lionel 4-4-2 RTR loco got kind of warm on the 031 oval with 3 plastic cars. Did not take it apart.

I also tested an MTH PS2 SW1 with the same train, cruise on and off. After about an hour, the motors were quite warm but not so hot that I couldn't touch it.

I know 031 isn't ideal and adds some extra drag but not as much to have issues. I don't have any die-cast cars, etc. I'd be curious to see results of GunrunnerJohn's test later.

I put the Williams Genesis A-A on the track with two track cleaning cars in trail (simulated load), and ran it for around 20 minutes at a good pace, probably around 60 scale MPH average.  I didn't feel any significant difference in the shell heat.  The bottom of the truck was at 105F, that's bolted directly to the motor.  That's hardly above room temperature, it's around 83 in here right now.  I tried again at a slower pace for another 15 minutes as that's at a lower spot on the DC motor efficiency curve.  The results were virtually identical.  The truck was 107F, but it was already warmed up from the previous run.

I confess I really didn't feel like taking them apart to measure actual motor temperature, but from the comments about the trucks getting hot, I figured this was close enough.

WP_20160527_001WP_20160527_002WP_20160527_003WP_20160527_004I have a set of older Williams NIB Texas Special F3s, ABA. I use them to pull my PW aluminum passenger cars. I read this post last night so I gave them a spin to day. My loop is 10 x14 and is FastTrack with 072 curves, is flat and level. It is a mite dirty, but to clean it its either stand on a latter or take it down, witch is on the near agenda. I run the set up; ABA and 7 Aluminum cars with a PW-ZW  with no more than a wipe and clean and visual inside inspection. Ran it for 30 to 40 minutes today, that's about a normal run, The engine rear motor was a little warm  but nothing to worry about, and the ZW; you could hardly feel any warmth at all. I don't run my trains hard but I do tend to run long heavy trains. I like to watch them go as slowly as possible ( slow train to Arkansas ).

Attachments

Photos (4)

Slow is the lowest efficiency for the can motors, hence the greatest heat buildup.  If they didn't get hot then, they shouldn't be an issue at faster speeds.

Yesterday at the club I was running my Santa Fe F3 ABBBA with 4 lionel dummys and 1 powered williams unit hauling 25 cars around the layout.  There are grades so sometimes the engine is barely crawling and sometimes it it racing along.  I ran this for about 5 hours with no noticeable heat buildup on either the trucks or the shell.

Rolland

If every motor you try is heating up, there is something in your track or transformer causing the problem, not that many motors all get hot at one time, have you taken the suspect engines to another track and tried running them to verify ?

I, like Rolland above, run long consists with grades. I seldom have a heating issue, I just upgraded a set of Lionel F-3 pullmor to Williams can motors and trucks, have both A units double motor, and run 15 aluminum passenger cars behind it for hours and they get warm but not hot. My layout is fastrack 048 and 060 with a Z4000. 

The few Williams I have had get hot had an issue with the truck or pickup, one also had a bad wire to the e unit which smoked the e unit but the motors were good to go once put a bridge rectifier in for forward only.

Paradise & Pacific Railroad

FWIW, I've had a number of Williams steam that had motors that really got hot and drew a lot of power.  Usually they get replaced during the upgrades.

I can't believe this thread came back to life after 3 years!

The Williams name has been around a long time, and I'm not sure what vintage of locomotive is being discussed in some of these posts.  But I'll make a general statement (which is the same thing I've been saying for the last 20 years.)  It's the gear ratio.  It's always been the gear ratio.  98% of the O gauge locos made are geared too tall (fast) for an adult application: continuous operation at modest speeds on a home-sized layout with sharp curves.  Going back to the first post in this thread, of course the "old timer" 4-6-0 runs cool, because its motor is operating in a healthy, sustainable RPM range.

Just about every vertically motored diesel ever made (there are a FEW exceptions) is geared too tall.  (I'll also observe that the vertical orientation greatly limits the length of the motor AND the available "head room" for a flywheel.)  Sure, speed control lets you run them at 5 mph or whatever.  But especially if you're also pulling a load, there's a LOT of heat build-up.  No easy way to change the gear ratio, and no easy way to remove the excess heat.  Maybe real operating exhaust fans?  Another gimmick and something else to fail!!

I can only guess that the manufacturers don't want to expend the effort to tame the noise, vibration, and harshness (NVH) issues which are more likely with high-rpm operation.  But a properly geared drivetrain is a beautiful thing.  Quality engineering design, good materials, and we would be running trains instead of discussing these problems. 

Creep, coast, and pull.  We're not talking about cold fusion here.

Ted S posted:

I can't believe this thread came back to life after 3 years!

The Williams name has been around a long time, and I'm not sure what vintage of locomotive is being discussed in some of these posts.  But I'll make a general statement (which is the same thing I've been saying for the last 20 years.)  It's the gear ratio.  It's always been the gear ratio.  98% of the O gauge locos made are geared too tall (fast) for an adult application: continuous operation at modest speeds on a home-sized layout with sharp curves.  Going back to the first post in this thread, of course the "old timer" 4-6-0 runs cool, because its motor is operating in a healthy, sustainable RPM range.

Just about every vertically motored diesel ever made (there are a FEW exceptions) is geared too tall.  (I'll also observe that the vertical orientation greatly limits the length of the motor AND the available "head room" for a flywheel.)  Sure, speed control lets you run them at 5 mph or whatever.  But especially if you're also pulling a load, there's a LOT of heat build-up.  No easy way to change the gear ratio, and no easy way to remove the excess heat.  Maybe real operating exhaust fans?  Another gimmick and something else to fail!!

I can only guess that the manufacturers don't want to expend the effort to tame the noise, vibration, and harshness (NVH) issues which are more likely with high-rpm operation.  But a properly geared drivetrain is a beautiful thing.  Quality engineering design, good materials, and we would be running trains instead of discussing these problems. 

A high gear ratio is not a panacea, I recently did command upgrades on a few Williams brass steamers with a 44:1 gear ratio.  While slow speed performance is obviously great, by the time you get to around 45 scale MPH, the motor is screaming at over 8,000 RPM!  Since most of the Mabuchi RS-5x5 motors top out near there, that's also the top speed.  Some of those motors have much lower RPM max, and really are not at all suitable for the task.

Timko has motors for Williams, the club buys them by the dozen, long or short shaft, they are quality replacements and last as long or longer than the original. We have dozens of Williams Locomotives running on our public controlled tracks, the only thing we have trouble with is the sacrificial gear failing with all the use they get. Timko also repairs those. If that is the problem with your engines, Timko is a great solution.

Paradise & Pacific Railroad

We've had this discussion before John.  44:1 is pretty extreme.  For a while my signature line was "30:1 or bust!" (meant for a steam loco with 1.25" drivers.)  Many steam locos are geared at 16:1 or less, which leaves a lot of room for improvement!

What you want is 800 RPM at 4 scale MPH, and a redline of about 12,000 RPM which would give you 60 scale mph on the top end.  Motor mounted in rubber grommets, balanced flywheel(s), and die-cast metal body for noise suppression.  I didn't come up with this on my own.  Kato HO scale diesels, and US Hobbies O scale brass from the 1960s delivered rock-solid performance by following this formula.  Of course these weren't toys meant for kids--but we're not kids anymore, and we're not paying Toys R Us prices either!

I'm not sure I ever measured one of those "Old-timer" Williams 4-6-0s.   But they are renowned for good running, and I'm going to guess they are geared at 25 or 30:1.  It's too bad Williams never went back and updated the rest of their product line with this kind of thinking.

Creep, coast, and pull.  We're not talking about cold fusion here.

Unfortunately, we're dealing with reality now, and a lot of that nifty stuff isn't found when I open up one of these for upgrade.

Add Reply

Likes (1)
Post
OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
330-757-3020

www.ogaugerr.com
×
×
×
×
×