What is a "Motor Gen" ?

[GENE]

Have a friend who has just purchased an MCI 9 and wants to make use a "Motor-Gen" in it.
Would appreciate fellow busnuts info on what a "Motor-Gen" is.  Has anyone used one of these in there conversion?

Your thoughts are appriciated.

Enjoying the journey in NC,
gene

[DrivingMissLazy]

Have a friend who has just purchased an MCI 9 and wants to make use a "Motor-Gen" in it.
Would appreciate fellow busnuts info on what a "Motor-Gen" is.  Has anyone used one of these in there conversion?

Your thoughts are appriciated.

Enjoying the journey in NC,
gene

I suspect he is somewhat mixed up. I say that because I was in the motor-generator business for over 30 years.  A true motor-generator is an AC motor driving an AC generator (alternator). Some may ask why would anyone want a unit with an AC motor driving an AC Generator? Well my primary business was frequency changing. I used a 60 hertz motor running at 1800 RPM to belt drive a 50 hertz generator at 1500 rpm which resulted in a 60-50 Hz. frequency changer.

I also built 50-60 Hz, 60-400hz, 50-400hz and several other combinations. ASdditionally I built 60-60 Hz power conditioners and 50-50 Hz power conditioners which were direct drive units.

I also manufactured engine generator sets. This is a gasoline or diesel engine driving an AC alternator. 

Based on that I believe your friend is looking for an engine generator or more commonly referred to as a gen-set. Except for one member of the bus nut community who insists on calling them noise makers. LOL

One thing that seems to cause confusion is that many people refer to an engine as a motor and that is not really correct. The original definition of a motor was a device that used AC or DC power as a motive force and an engine is an internal combustion device using a fuel such as gasoline as a motive force.
Richard

[Greg Roberts]

I recall the term used in the yacht world at one time and the device was typically a DC generator directly (no battery involved) feeding a square-wave AC inverter. These were/are also called a cruise generator.

[NCbob]

Many, many years ago I made my first trip from Detroit to Fort Lauderdale on an old 58' Petersen yacht which, while it had a small diesel generator, used a "Motor Generator" to keep the refrigerator running while underway.  It consisted of a 24VDC motor turning an 1750 RPM AC motor which created 115 Volts for the fridge.  It was a few cycles off but the fridge didn't seem to mind.

Do you suppose this is what he had in mind?

NCbob

[DrivingMissLazy]

I recall the term used in the yacht world at one time and the device was typically a DC generator directly (no battery involved) feeding a square-wave AC inverter. These were/are also called a cruise generator.

I assume the DC device was being driven by either an output shaft on an engine or directly by the propulsion drive shaft. Since the drive shaft/propeller was  generally a set rpm while cruising, it made an excellent device for creating AC power without operating the a genset.

If there was a square wave inverter involved, I would then suspect that it was a DC alternator, not DC  generator. In history, the DC alternator came before the advent of the square wave inverter.

I also manufactured cruise generators for applications such as this. There was no need, in my case, for the DC components since I operated a synchronous alternator directly from an output shaft on the output transmission. Various methods were utilized but typically it was an electrical clutch that coupled the shaft to the alternator after the yacht got up to cruising rpm.

Another type of motor generator that you might possibly run into was called a dynamotor. A trade name possibly. It consisted of a low voltage DC motor in the 6 to 24 volt range coupled to a DC generator that outputted typically 300 volts DC. This was utilized for suppling B+  plate voltage for vacuum tubes. Long before many of your times however. LOL
Richard

Richard

[Len Silva]

I think he may be talking about a rotary inverter, a small generator driven by a DC motor. I think one brand was "Redline" but my memory is fuzzy on that (happens a lot lately). They were VERY inefficient compared to todays electronic units but were a true sine wave output.

Len

[DrivingMissLazy]

I think he may be talking about a rotary inverter, a small generator driven by a DC motor. I think one brand was "Redline" but my memory is fuzzy on that (happens a lot lately). They were VERY inefficient compared to todays electronic units but were a true sine wave output.

Len

And in addition to being very inneficient they also contained a large number of carbon brushes as well as slip rings and commutator bars, all of which were subject to consideerable wear.
Richard

[OneLapper]

Hi guys,

I am completely new to the conversion coach scene.  My wife and I purchased three weeks ago a 1964 PD4106  with a 8V71 w/ 4 spd that was converted in the late 80s.  I run an equipment dealership so the mechanical side of things I'm pretty comfortable with, but more on that later.

My question is:  Does anyone use the aux drive that is used to run the over-the-road a/c for any other purpose, such as some type of generator?  I don't know what the reduction ratio of the shaft is yet, but it apprears that it's beefy enough to spin a 10kw gen head.

I'm glad that I came across this forum.  Seems like a bunch a nice people deviod of attitudes towards the noobs like me!

Mark

[DrivingMissLazy]

Hi guys,

I am completely new to the conversion coach scene.  My wife and I purchased three weeks ago a 1964 PD4106  with a 8V71 w/ 4 spd that was converted in the late 80s.  I run an equipment dealership so the mechanical side of things I'm pretty comfortable with, but more on that later.

My question is:  Does anyone use the aux drive that is used to run the over-the-road a/c for any other purpose, such as some type of generator?  I don't know what the reduction ratio of the shaft is yet, but it apprears that it's beefy enough to spin a 10kw gen head.

I'm glad that I came across this forum.  Seems like a bunch a nice people deviod of attitudes towards the noobs like me!

Mark

First of all, welcome aboard Mark. I hope you enjoy this board and your 4106. It is a great bus.

To answer your question, the 10 kw generator (alternator)  head has to spin at exactly 1800 rpm to generate 60 hertz power. On a yacht it is fairly easy to do this for hours or days on end while cruising.

Unfortunately when cruising in your 4106 the rpm is going to vary constantly so it is not feasible to run an AC alternator off this shaft. It would be feasible to run a DC alternator off this shaft and use  a DC to AC inverter to generate AC power while cruising. Just do not forget that while you are stopped or camping out, you would still need an engine generator for your AC power needs.

Again, welcome aboard.
Richard

[Greg Roberts]

Yes it was belt driven from the port engine and the inverter made do hertz AC no matter the engine RPM. Of course the wattage available was entirely related to the engine RPM but I recall that full 3500 watts were available at something like 1500 RPM. The literature referred to the unit as a DC generator rather than a DC alternator but it could have been as you say Richard. The device worked well and never really needed my attention so I did not get too deeply into actual research of each component. I used dual alternators feeding my house system and that was the system I used mostly under way. Occassionally I did run the genset but, in the cool climate of the Washington State and Southeast Alaskan waters, the electrical loads were low.

I recall the term used in the yacht world at one time and the device was typically a DC generator directly (no battery involved) feeding a square-wave AC inverter. These were/are also called a cruise generator.

I assume the DC device was being driven by either an output shaft on an engine or directly by the propulsion drive shaft. Since the drive shaft/propeller was  generally a set rpm while cruising, it made an excellent device for creating AC power without operating the a genset.

If there was a square wave inverter involved, I would then suspect that it was a DC alternator, not DC  generator. In history, the DC alternator came before the advent of the square wave inverter.

I also manufactured cruise generators for applications such as this. There was no need, in my case, for the DC components since I operated a synchronous alternator directly from an output shaft on the output transmission. Various methods were utilized but typically it was an electrical clutch that coupled the shaft to the alternator after the yacht got up to cruising rpm.

Another type of motor generator that you might possibly run into was called a dynamotor. A trade name possibly. It consisted of a low voltage DC motor in the 6 to 24 volt range coupled to a DC generator that outputted typically 300 volts DC. This was utilized for suppling B+  plate voltage for vacuum tubes. Long before many of your times however. LOL
Richard

Richard

[FloridaCliff]

Len,

Yes they are "Rediline"

I have a 500 and 1500 watt units.

I use the 500 under the hood of my Jeep to do jobs out on the property that are too far for an extension cord.

They are real battery Hogs and don't produce very clean power.

Cliff

[boogiethecat]

... and there's also "Auragen" which is an oversized alternator with an electronics package that makes pure 120 volt sine wave power to about 5Kw regardless of engine speed. 
They found a lot of use in ambulances and were/are *much* more pricey than a big Trace inverter but are slowly being seen more on ebay an other surplus places (none there now though)

[NJT5047]

Hi Gene,
From the previous posts, I now have some idea what a Motor-Gen is, but most MC9s have 50DN alternators...225-270 amps plus (a sort of Mega Moto Gen in itself).   With the large alternator and an inverter, his electrical needs should be easily met.   One AC will operate off the power available from a 50DN and a quality inverter.  All this using the bus 24V system too.  No special wiring or complexity.   From the descriptions offered up so far, a Motor-Gen sounds like old technology.  I remember something similar used in motorhomes.  It was noisy...made a constant whine...seems the term "Dynamotor" may have been used to describe them...?? 
Come see me sometime! I'm still 5 minutes away from you (unless you have moved?)!  Is your MCI friend local?  Guy has an MC9 stuck in a backyard off Secrest Short Cut.  Bus conversions seem to be all over.
Put October 5-8th on your calendar for Dallas' next bus gathering...the last one was a hoot!  Only two hours away. 
Regards, JR

[OneLapper]

Rich,

Thanks for the reply.  The previous owner removed some of the original a/c system, but the compressor and clutch unit is still in place (although he did disconnect the coupler to the engine output shaft).  I imagine I'll remove the unit to save weight which leave a nice empty compartment.  It looks like there is a triple belt pulley setup already attached to the clutch housing.  That could be used to drive a second alternator.

Mark