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AC speed reduction

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AC speed reduction
Posted by mkepler954 on Sunday, June 4, 2017 10:17 PM

Just finished building a Faller Chairoplane kit# 140315 which has an AC brushless motor (round yellow type).  I hooked it up to the 20VAC assessory terminals of an old train transformer.  When I turned it on, it spun way too fast.  How do I reduce the speed?  The motor came with no gear reduction cog wheels to replace inside the motor.   

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Posted by zstripe on Monday, June 5, 2017 3:12 AM

Lower the input voltage.....20VAC is too high. They say it requires 16VAC to power it and that is probably what the lighting is rated for. You can even go to 12VAC if 16vac is still too fast. You should be able to get a Wall-wart plug in for it in just about any AC voltage You want.

Take Care! Big Smile

Frank

What the power supply recommendations are:

 (Requires Part# 163053 16VAC Power Supply) 

 

 

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Posted by gregc on Monday, June 5, 2017 3:46 PM

what about using a reostat from an older throttle ?

greg - Philadelphia & Reading / Reading

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Posted by richg1998 on Monday, June 5, 2017 4:39 PM

gregc

what about using a reostat from an older throttle ?

 

I did that about thirty years ago with a rheostat out of the junk box. I just looked at ebay and many rheostats for sale. Just figure out the necessary wattage knowing the motor current.

http://www.resistorguide.com/rheostat/

Rich

 

 

 

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Posted by mkepler954 on Monday, June 5, 2017 9:19 PM
I found a 12Vac wallwart in my stash of power supplies and hooked it up. The motor speed was identical to the 20Vac I previously used.
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Posted by mkepler954 on Monday, June 5, 2017 9:35 PM
I hooked up a Lionel Multi-Control Trainmaster Transformer to the motor. The speed did not change whether I used 9Vac, 10Vac, 15Vac or 19Vac.
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Posted by richg1998 on Tuesday, June 6, 2017 1:05 AM

mkepler954
I hooked up a Lionel Multi-Control Trainmaster Transformer to the motor. The speed did not change whether I used 9Vac, 10Vac, 15Vac or 19Vac.
 

Did you actually measure the voltage with a voltmeter or just set according to the numbers on the transformer? Brushless motors usually draw low current.

Rich

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Posted by zstripe on Tuesday, June 6, 2017 6:20 AM

You could try a cheap light dimmer, but I'm not positive it will work without cutting down too much of the sine wave to the motor and motor won't run hardly at all and get hot. Look for one that states Triac light dimmer. It could possibly work for such a low current motor, but the dimmer may have too much resistance for a single phase motor. Been a very long time since I messed with low voltage AC motors......especially brush-less ones.

Good Luck! Big Smile

Frank

EDIT: Does that ride have incandesant lighting also? If changing the voltage like You say You did and the speed is the same. What does the lighting do? Does that change at all?

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Posted by AlienKing on Tuesday, June 6, 2017 11:53 AM

My guess is the speed of the motor is based on the 60hz input, and not the voltage.  It could be that your kit was designed around the 50hz power in Europe.

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Posted by speedybee on Tuesday, June 6, 2017 1:03 PM

AlienKing

My guess is the speed of the motor is based on the 60hz input, and not the voltage.  It could be that your kit was designed around the 50hz power in Europe.

Agreed... unless my unserstanding of AC motors is totally wrong (which it could be), on most of them the speed is directly controlled by the AC frequency, not the voltage. The voltage, and therefore current, would only alter how much torque the motor is capable of producing.

I think you could build a variable frequency AC generator fairly cheaply using something like a L293D and a 555 timer, and make the speed whatever you want.

Alternatively if you're not at all into electronics and there's some room to work with in/under the chairoplane, you could buy a cheap gear set to put between the motor and the chairoplane, or fashion your own with a couple wheels of different diameter connected by a rubber band.

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Posted by richg1998 on Tuesday, June 6, 2017 1:41 PM

I have done some Internet searching for

brushless ac motor control circuit

and it seems that frequency control is necessary.

Give it a try.

Rich

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Posted by rrinker on Tuesday, June 6, 2017 5:57 PM

 Depends on the type of motor. A shaed pole motor, or what's known as a synchronous motor as used in mechanical electric clocks is frequency dependent and a change in voltage will have little effect once you get over the bare minimum to operate it, all the way up until the voltage is so high it cooks the thing. However,  wound field motor liek sued in old Lionel trains is indeed voltage controlled, otherwise the variable voltage transformers would never have been able to control the speed.

 That little Faller motor is almost surely a synchronous type. SOmewhere I have one from the early 60's, part of a mill, that turned the water wheel - yes, it's Faller, but it was a wood kit. That motor absolutely is a synchronous clock type motor.

                            --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by zstripe on Tuesday, June 6, 2017 5:59 PM

speedybee

 

 
AlienKing

My guess is the speed of the motor is based on the 60hz input, and not the voltage.  It could be that your kit was designed around the 50hz power in Europe.

 

 

Agreed... unless my unserstanding of AC motors is totally wrong (which it could be), on most of them the speed is directly controlled by the AC frequency, not the voltage. The voltage, and therefore current, would only alter how much torque the motor is capable of producing.

I think you could build a variable frequency AC generator fairly cheaply using something like a L293D and a 555 timer, and make the speed whatever you want.

Alternatively if you're not at all into electronics and there's some room to work with in/under the chairoplane, you could buy a cheap gear set to put between the motor and the chairoplane, or fashion your own with a couple wheels of different diameter connected by a rubber band.

 

I also agree......that's what I was getting at with the sine wave. There are circuits that can be made to do just that. But You would need more info about the motor, which is not available and it has been many yrs. since I attempted to do any of that. I had to work on some Akai reel to reel tape-recoders that had to work on 100vac 50hz to change motor speed, but heck that was back in the 60's....been a long time for this old brain.

Good Luck! Big Smile

Frank

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Posted by gregc on Tuesday, June 6, 2017 7:10 PM

weren't the old Lionel trains AC?   how was speed controlled?   or was is rectified AC?

greg - Philadelphia & Reading / Reading

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Posted by 7j43k on Tuesday, June 6, 2017 11:14 PM

As Randy said just above, there are AC motors where the motor speed is frequency dependant, and there are ones where the motor speed is voltage dependant.

The motors in standard Lionel trains are the latter.  They are AC motors that run on, yes, AC.

The motors in old electric clocks are the former.  They are also AC motors that run on AC.

 

Which version the motor under discussion is is still (perhaps) under discussion.

 

 

Ed

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Posted by mkepler954 on Tuesday, June 6, 2017 11:41 PM

I used 2 voltmeters just to be sure.  Both matched the output shown.

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Posted by mkepler954 on Tuesday, June 6, 2017 11:50 PM
Yes, it is a synchronous motor, Faller# 180629
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Posted by richg1998 on Wednesday, June 7, 2017 9:37 AM

Again, frequency is the issue. a Synchronous Motor.

The label says it all.

The voltage limit is only to keep the current in the ballpark. Something I forgot because I was comparing this to a DC motor for speed control.

https://en.wikipedia.org/wiki/Synchronous_motor

Google Faller# 180629.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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