Noisey Lionel 1991 NYC Mohawk #18002

It’s a pullmor motor under a die cast shell. They are noisy. I tried and tried to quiet mine but never could get lt done. I just lived with it until I switched to a can motor. All those pullmors in steamers from the mid 80’s and 90’s are just grinders. They run great but are just noisy. 

Rod is right, did the same thing he did....only way to stop the growl was to can motor it...

When I installed TMCC in my Mohawk I used an early generation LCRU2 and the noise got much worse Pulse width modulation speed control and all, so I set about trying to find a solution and whether I could quiet it down. I found it was much quieter with the rear trailing truck and ash pan removed. I tried it with the ash pan only and it was better than the pan and truck together but still made more noise than when it was off. What I did notice was how close the steel ash pan was to the field laminations and the armature. The magnetic field from the stator is reversing at 60hz and as the armature turns it's poles are also interacting with the ash pan as well as the stud that connects the rear truck with the pan all of this is vibrating in unison with the motor and it's stray magnetic forces. It is not the gear box !  I had some copper sheet about the same thickness as the original ash pan so I fashioned a new ash pan out of copper and made a new stud to connect the rear truck out of brass. I then coated the inside surfaces of the firebox and ash pan with liquid rubber to cut reverberations. I think 1/8" cork might even be better. Lowes and HomeDepot both sell cork for bulletin boards that I may yet give a try.   All of this together made a BIG difference in what I think is referred to as Pullmor growl.  It is not as quiet as a DC can motor but never the less much better than before.  In years past I ran two rail scale locos that had universal AC/DC motors such as the Lionel Pullmor that did not growl the way the Lionel motors do but they were 7pole for the K&D motors and the Lobaugh motors are 9 poles.  I have run both on AC as well as DC and they don't growl a bit.  For years I searched for a 5 or 7 pole armature the same diameter as the armature in the pullmor to see if I could install one in the Pullmor frame. No luck yet. What I did do is Install a 7 pole K&D in my 18009. It was more of an incremental improvement in addition to the ash pan but requires a bit of machining to the loco frame that most would not want to take on. Now running the K&D with PWM from the LCRU2 board does produce a little more noise than on straight AC or DC but it's still quieter by a good bit than the Pullmor. Haven't matched a DC can yet but getting close. I think ditching the LCRU board and installing an ERR AC commander may be the magic pill as it's PWM frequency is much higher than the LCRU board. Though I'm happy with where it is, much better than when I started.  In a sense the ash pan on locos with pullmor motors such as the Mohawk and Hudson is acting as a pole keeper and a speaker cone at the same time. Pullmor motors run on DC don't induce this interaction between the magnetic field in the motor and near by ferrous metals. If you put one of these locos on blocks and hold the ash pan near the bottom of the motor you can feel this interaction when you run the motor. But switch to DC and even though there will be an attraction to the stator laminations it does not introduce the audio component that AC current does.  j

Just to dispel any confusion, the #3000 Mohawk from '90-'91 product number is 18009.  18002 is the #785 Hudson from '87.

What, me worry? 

JohnActon posted:

When I installed TMCC in my Mohawk I used an early generation LCRU2 and the noise got much worse Pulse width modulation speed control and all, so I set about trying to find a solution and whether I could quiet it down. I found it was much quieter with the rear trailing truck and ash pan removed. I tried it with the ash pan only and it was better than the pan and truck together but still made more noise than when it was off. What I did notice was how close the steel ash pan was to the field laminations and the armature. The magnetic field from the stator is reversing at 60hz and as the armature turns it's poles are also interacting with the ash pan as well as the stud that connects the rear truck with the pan all of this is vibrating in unison with the motor and it's stray magnetic forces. It is not the gear box !  I had some copper sheet about the same thickness as the original ash pan so I fashioned a new ash pan out of copper and made a new stud to connect the rear truck out of brass. I then coated the inside surfaces of the firebox and ash pan with liquid rubber to cut reverberations. I think 1/8" cork might even be better. Lowes and HomeDepot both sell cork for bulletin boards that I may yet give a try.   All of this together made a BIG difference in what I think is referred to as Pullmor growl.  It is not as quiet as a DC can motor but never the less much better than before.  In years past I ran two rail scale locos that had universal AC/DC motors such as the Lionel Pullmor that did not growl the way the Lionel motors do but they were 7pole for the K&D motors and the Lobaugh motors are 9 poles.  I have run both on AC as well as DC and they don't growl a bit.  For years I searched for a 5 or 7 pole armature the same diameter as the armature in the pullmor to see if I could install one in the Pullmor frame. No luck yet. What I did do is Install a 7 pole K&D in my 18009. It was more of an incremental improvement in addition to the ash pan but requires a bit of machining to the loco frame that most would not want to take on. Now running the K&D with PWM from the LCRU2 board does produce a little more noise than on straight AC or DC but it's still quieter by a good bit than the Pullmor. Haven't matched a DC can yet but getting close. I think ditching the LCRU board and installing an ERR AC commander may be the magic pill as it's PWM frequency is much higher than the LCRU board. Though I'm happy with where it is, much better than when I started.  In a sense the ash pan on locos with pullmor motors such as the Mohawk and Hudson is acting as a pole keeper and a speaker cone at the same time. Pullmor motors run on DC don't induce this interaction between the magnetic field in the motor and near by ferrous metals. If you put one of these locos on blocks and hold the ash pan near the bottom of the motor you can feel this interaction when you run the motor. But switch to DC and even though there will be an attraction to the stator laminations it does not introduce the audio component that AC current does.  j

Hi John,

Thank you for your input and idea. The weird thing is that the Mohawk will make this sound while my 785 ((18002) doesn't. But it may have to do with the longer drive train. But converting over to a can motor may not be an option as this engine was converted to TMCC by Train America Studios.  Again thank you for sharing your knowledge and will try the sound proofing.

Mine sounds like it's grinding rocks, I'm running it now.

Dennis Rempel posted:

Mine sounds like it's grinding rocks, I'm running it now.

How can that be enjoyable?

Jeff T posted:

Dennis Rempel posted:

Mine sounds like it's grinding rocks, I'm running it now.

How can that be enjoyable?

maybe he enjoys the sound of rocks grinding!....not sure that'd be my cup of tea...but to each his own!!!..

JohnActon posted:

What I did notice was how close the steel ash pan was to the field laminations and the armature. The magnetic field from the stator is reversing at 60hz and as the armature turns it's poles are also interacting with the ash pan as well as the stud that connects the rear truck with the pan all of this is vibrating in unison with the motor and it's stray magnetic forces. It is not the gear box ! 

I did some work on the smoke unit of my Mohawk, and afterward, I noticed the same alarmingly loud grinding sound that the OP reported.  When I investigated more closely, I discovered that I hadn't tightened the ash pan screws all the way, and as you say, it was vibrating something fierce.

One I made certain all the screws were snugged down as far as they could go, the racket was gone.

I had some copper sheet about the same thickness as the original ash pan so I fashioned a new ash pan out of copper and made a new stud to connect the rear truck out of brass. I then coated the inside surfaces of the firebox and ash pan with liquid rubber to cut reverberations. I think 1/8" cork might even be better.

I admire your ingenuity and willingness to experiment. Though in my case, at least, making nonmagnetic parts wasn't necessary -- just making sure the existing ash pan was tight and immobile.

 

 

Balshis posted:

JohnActon posted:

What I did notice was how close the steel ash pan was to the field laminations and the armature. The magnetic field from the stator is reversing at 60hz and as the armature turns it's poles are also interacting with the ash pan as well as the stud that connects the rear truck with the pan all of this is vibrating in unison with the motor and it's stray magnetic forces. It is not the gear box ! 

I did some work on the smoke unit of my Mohawk, and afterward, I noticed the same alarmingly loud grinding sound that the OP reported.  When I investigated more closely, I discovered that I hadn't tightened the ash pan screws all the way, and as you say, it was vibrating something fierce.

One I made certain all the screws were snugged down as far as they could go, the racket was gone.

I had some copper sheet about the same thickness as the original ash pan so I fashioned a new ash pan out of copper and made a new stud to connect the rear truck out of brass. I then coated the inside surfaces of the firebox and ash pan with liquid rubber to cut reverberations. I think 1/8" cork might even be better.

I admire your ingenuity and willingness to experiment. Though in my case, at least, making nonmagnetic parts wasn't necessary -- just making sure the existing ash pan was tight and immobile.

 

 

 

I made sure everything was tight. No practical way to take all the slack out of the post that holds the trailing truck to the ash pan.   The bearing tolerance on the Pullmor motors from the factory was very broad and I have noticed some of my motors are fairly quiet and some make quite a bit more noise. My definition of quiet may be different than yours. I was shooting for making a Pullmor as quiet as a can, while running on Pulse Width Modulation (TMCC) speed control which opens a whole new can of worms in inducing vibrations.  Adding more poles to the motor raises the frequency of the vibrations but lowers the amplitude by quite a bit. This may also take the magnetic pulses caused by the armature above the resonance frequency of the ash pan ?? What I do know is that with the addition of the 7 pole K&D motor and the non ferrous parts it is quieter running on PWM than the pullmor was running conventional. By a lot.  j

mikie posted:

JohnActon posted:

When I installed TMCC in my Mohawk I used an early generation LCRU2 and the noise got much worse Pulse width modulation speed control and all, so I set about trying to find a solution and whether I could quiet it down. I found it was much quieter with the rear trailing truck and ash pan removed. I tried it with the ash pan only and it was better than the pan and truck together but still made more noise than when it was off. What I did notice was how close the steel ash pan was to the field laminations and the armature. The magnetic field from the stator is reversing at 60hz and as the armature turns it's poles are also interacting with the ash pan as well as the stud that connects the rear truck with the pan all of this is vibrating in unison with the motor and it's stray magnetic forces. It is not the gear box !  I had some copper sheet about the same thickness as the original ash pan so I fashioned a new ash pan out of copper and made a new stud to connect the rear truck out of brass. I then coated the inside surfaces of the firebox and ash pan with liquid rubber to cut reverberations. I think 1/8" cork might even be better. Lowes and HomeDepot both sell cork for bulletin boards that I may yet give a try.   All of this together made a BIG difference in what I think is referred to as Pullmor growl.  It is not as quiet as a DC can motor but never the less much better than before.  In years past I ran two rail scale locos that had universal AC/DC motors such as the Lionel Pullmor that did not growl the way the Lionel motors do but they were 7pole for the K&D motors and the Lobaugh motors are 9 poles.  I have run both on AC as well as DC and they don't growl a bit.  For years I searched for a 5 or 7 pole armature the same diameter as the armature in the pullmor to see if I could install one in the Pullmor frame. No luck yet. What I did do is Install a 7 pole K&D in my 18009. It was more of an incremental improvement in addition to the ash pan but requires a bit of machining to the loco frame that most would not want to take on. Now running the K&D with PWM from the LCRU2 board does produce a little more noise than on straight AC or DC but it's still quieter by a good bit than the Pullmor. Haven't matched a DC can yet but getting close. I think ditching the LCRU board and installing an ERR AC commander may be the magic pill as it's PWM frequency is much higher than the LCRU board. Though I'm happy with where it is, much better than when I started.  In a sense the ash pan on locos with pullmor motors such as the Mohawk and Hudson is acting as a pole keeper and a speaker cone at the same time. Pullmor motors run on DC don't induce this interaction between the magnetic field in the motor and near by ferrous metals. If you put one of these locos on blocks and hold the ash pan near the bottom of the motor you can feel this interaction when you run the motor. But switch to DC and even though there will be an attraction to the stator laminations it does not introduce the audio component that AC current does.  j

Hi John,

Thank you for your input and idea. The weird thing is that the Mohawk will make this sound while my 785 ((18002) doesn't. But it may have to do with the longer drive train. But converting over to a can motor may not be an option as this engine was converted to TMCC by Train America Studios.  Again thank you for sharing your knowledge and will try the sound proofing.

Mikie.  Doesn't the motor in the 785  sit back a bit further into the cab and over a large cutout in the ash pan so there is less interaction with the ash pan. Not sure but I think it is a bit higher in the frame so that adds a bit more isolation to the ash pan.  The motor in the Mohawk and Reading T1 is in the firebox centered directly over the ash pan. I have not converted my T1 and 700e to TMCC yet so cannot say what problems I may encounter when I do.  Hopefully I can use ERR AC Commanders which have a higher frequency PWM than the early TMCC boards when I finally get to them.   j