1. #1
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    Default PTO or Diesel generator on pumper

    My department is getting a new pumper and there is controversy, right now it is between a PTO diven generator or a Diesel generator. Some don't like the diesel generators becasue recently we have had many problems with them breaking down. Does anyone have an experience with PTO driven ones, especially if you ahve used both. Also does anyone have any literature on the subject expecially if they are compared togeather. We are having problems where people's ego's are getting in the way. We wanted to have a drivers from Bridgeport and Waterbury to come over and help with spec out the truck, becasue driving and knowing the trucks are their jobs and they would be more knowlegable than our volly company that does 300 runs a year. People at our firehouse, mainly the older guys said to us when we suggested it "what, our opinion doesn't count?". Any assistance would be appreciated.


    David Larson

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    Never have used a diesel generator on a rig. We switched to PTO's from gas on two of our new rigs. We like them since they dont make any noise, dont take up as much room as a gas/diesel generator, no re-fuelimg and you can mount them pretty much any place since you dont have to worry about having enough ventilation or cooling for the motor. And no gas/diesel fumes. Any new rigs we buy will have PTO generators.

    Dave

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    Default pto

    We recently purchased an Air/Light rescue- it has a 40KW pto generator on it and we love it- there is very little maintenance and they take up less space than an equally sized diesel generator

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    Thumbs up

    We went to PTO from diesel and will never go back. We have had some problems, but nothing that would keep us froming specing PTO driven in the future. We had AMPS, but you can check the history in the forum to see discussions comparing different PTO brands.

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    We have diesel generators on all our trucks. We used to get "generacs" that required higher rpm's to provide enough juice. Problem we ran into was at low rpm's, we had no lights. Diesel generator took care of that problem. As a side note, the alternator belt on our truck broke at a fire call. Was not noticed until the batteries were fairly drained already. We were able to use the diesel generator to plug the trucks battery charger into while at the scene and also on the ride back.

    Do the new style PTO generators not have the rpm requirements of the old days?
    "This thread is being closed as it is off-topic and not related to the fire industry." - Isn't that what the Off Duty forum was for?

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    Our newest truck has a PTO on it and its great.....all our new truck will have those as part of the spec.
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    Originally posted by Bones42
    Do the new style PTO generators not have the rpm requirements of the old days?
    Bones I have used both Harrison and AMPS generators and I have not ever had the need to bring the rpms up on our large apparatus to get max capacity ever. Now I have had to bring up the rpms on our 2001 F-550 light rescue, but that is because of the way the Ford tranny operates (you need 1000 rpm to get any real torque to the pto).

    I don't normally quote manufacturers but it fits in this case her are quotes from their respective web site FAQs.

    AMPS
    "Hydraulics allow our generator to spin at a constant RPM even with variable engine speeds and loads. In most applications, AMPS hydraulic generators provide clean, quality power from engine idle to engine redline."


    Harrison
    "Do I have to maintain a constant rpm at my vehicle's engine?
    No. Our pump compensates for rpm fluctuations. It does not matter if you are at idle or driving down the road; you can get full power anytime, all the time!"

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    We have a PTO generator on our rescue truck. Most unreliable piece of equipment we've ever owned. Been a problem since day one, and E-One has yet to get it straightened out. We've had to add a portable generator to the truck just because we EXPECT the PTO gen. to fail when we need it. We'll never do it again.
    That being said, we have two diesel generators- one on an engine, one on a ladder. The one on the engine is also less than reliable- it appears to be a chronic overheating problem. The one on the ladder is a dream- never lets us down. Odd, since the one on the ladder is enclosed in the pump compartment and the one on the engine is on top of the truck. Go figure....
    TW
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    Have you considered an AuraGen engine driven generator? I'm not sure of your power requirements but AuraGens come in 5 kw and 8.5 kw versions. I have one on our HazMat truck (in a chemical plant) and it has never given any trouble. It is belt driven and works well even at idle speed. It has worked so well that I am purchasing one for my service truck at my volunteer department.

    Lewie

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    We just put our first PTO Gen set in-service, the other 7 in the fleet are Onan 7.5 Diesel or Honda Gas 5.0. The Harrison 10KW frees up some room in the basket area (over the Pump). The unit has been well received and our repair shop likes the fact they do not have to maintain another motor. Having Air-conditioning we normally run the main power plant for heating or cooling so that is not an issue. The only issue that we are having with the unit is engagement. The factory dashboard instructions state that you have to be at engine idle to engage??? This in not the real world with our other type of gen sets we typically start these units on the way to the fire or auto accident. I have spent a great deal of time on the phone and Email with Chelsea (PTO) and Harrison (Gen Set). While both companies have agreed to allow a 1600 RPM engagement I have not received a written confirmation. With no confirmation on engagement, with this type procedural change we could be going back to the tried and true Onan 7.5.

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    Out of curiosity, why do you start them so much ahead of time?

    If it's for the reason we start our generator early, it's to let it warm up before putting a load on it.

    I am also a member of an EMS Squad that has a rescue truck with a PTO generator on it. Once the PTO is engaged, there is no warm up time needed, it's instant power, so there is no need to worry about it being engaged until it's needed.
    "This thread is being closed as it is off-topic and not related to the fire industry." - Isn't that what the Off Duty forum was for?

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    I think the bad rap PTO generators get is from back when they were directly driven off the pto, and there were some hassles with running the generator and pumping.

    With the Hydraulically driven PTO generators, they compensate for changes in RPM

    The only advantage I can see of a Diesal generator is that if your engine quits for some reason, you can still run the generator

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    We have had mounted Diesel generators on our apparuatus up into our last new pumper which was spec'ed out with an AMPS PTO generator, I don't think we will be going back to mounted generators, the PTO is quiet almost no maintance and no lost compartment space as the mounted diesel generators are not at all quiet lots of maintance just a real pain in the ***** at time with repairs lost compartment space and heavy.
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    Originally posted by pfd3501
    I think the bad rap PTO generators get is from back when they were directly driven off the pto, and there were some hassles with running the generator and pumping.

    With the Hydraulically driven PTO generators, they compensate for changes in RPM

    The only advantage I can see of a Diesal generator is that if your engine quits for some reason, you can still run the generator
    I think PFD hit it here... if you go with a hydraulically driven PTO, you are relatively freed from RPM issues.

    The direct-drive PTO's or split-drive shaft powered generators (like most water pumps) are typically RPM dependant.

    We have a 15kw AMPS and a 15kw Harry... no problems with either. If possible, I'd recommend hotshift PTO's that can be engaged while the vehicle is in motion. Only one of our trucks came through this way.
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    We currently have two rigs without generators because they are both at amps being rebuilt, first one that broke is a 2 year old 15 kw, the second one is one year old 10 kw. The problem may be related to them running all the time, so that we can light up a scene as we pull up, all of our rigs before these two had onan diesels, cant remember much trouble with them as long as we started them before pulling out in cold weather.

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    On 2 of our pumpers we have diesel gens onboard, our older unit (1995 Pierce) has it mounted in the front pass compt, the drawbacks to that is, 1. takes up a compt, and 2. you have to make sure to keep the door open so it won't overheat (you have to start it right on the gen). On our newest Pumper (2001 Pierce saber) the gen is mounted above the pump cavity on the pass side, there are 2 different places to start it..1. in the front upper drivers compt where the breaker panel is, and 2. inside the cab, so you can start it as you arrive on scene. The both run off of the truck fuel tanks, so you don't have to worry about an aux tank running dry.
    The comments made by me are my opinions only, not of the Fire and EMS services I am affiliated with.

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    Several truck mfg reps have told me that with hot shift, you need to have your RPMs below 1800 before engaging the pto. Shouldn't be a biggie, but it is a communication and training issue.

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    On our newest Pumper (2001 Pierce saber) the gen is mounted above the pump cavity on the pass side, there are 2 different places to start it..1. in the front upper drivers compt where the breaker panel is, and 2. inside the cab, so you can start it as you arrive on scene. The both run off of the truck fuel tanks, so you don't have to worry about an aux tank running dry.
    we have this on our 1984 Pierce and love it .......we have a button the pump panel also along with a preheat one.
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    Originally posted by Weruj1
    On our newest Pumper (2001 Pierce saber) the gen is mounted above the pump cavity on the pass side, there are 2 different places to start it..1. in the front upper drivers compt where the breaker panel is, and 2. inside the cab, so you can start it as you arrive on scene. The both run off of the truck fuel tanks, so you don't have to worry about an aux tank running dry.
    we have this on our 1984 Pierce and love it .......we have a button the pump panel also along with a preheat one.
    201, I think you forgot to quote it. I was just about to ask myself when you got a new truck!!!

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    yes I did ..........
    IACOJ both divisions and PROUD OF IT !
    Pardon me sir.. .....but I believe we are all over here !
    ATTENTION ALL SHOPPERS: Will the dead horse please report to the forums.(thanks Motown)
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    I'm sorry, I haven't been paying much attention for the last 3 hours.....what were we discussing?
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    http://www.firehouse.com/forums/show...60#post1137060post 115

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    Both Hydraulic/PTO and Diesel Generators work well. On a new truck, initial cost on either will be similar. At this point, both are fairly well, and are well developed for the fire service

    Advantage of either, can be engaged rolling up to a scene, allowing a lot of light if necessary

    Advantage of Diesel Generator: Can run independent of the truck
    Disadvantage of Diesal Generator: Can be loud, placement so it can cool is an issue

    Advantage of Hydraulic Generator - quiet
    Disadvantage: is the trucks engine stops, your done.

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    Have worked with both types and both have served us well.
    I like the PTO better because you have instant power upon
    arrival at the scene, just flip the switch. Less maintenance
    too.

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    Default Hold your breath...this will be short....

    There is obviously some confusion here on the wording utilized as “PTO Generator”. Definition: Power Take Off. Maybe I can shed some light on the subject in a simplistic way that will be useful to “someone”, I hope.

    ALL generators have what is called a “two bearing alternator”, yes and alternator! It is a bunch of copper wound around to make a big ball. The “ball” (technically called a “w(h)inding”) that spins and then produces an electrical field that is captured to produce electricity. I know there are some electric guru’s out there that can describe it a lot better than me, sorry! If there is some guy out there named “Sparky” that wants to share his or her wisdom, feel free to add to my description! The “alternator” is driven by some “device” or power source. Be it: belt drive, gasoline engine, diesel engine, “pto”, “split shaft” gearbox pto or hydraulic.

    Being that the original post was for “Diesel or PTO”, I will spend most of my written boredom on those two devices requested. Furthermore, being that belt drive and gas were mentioned, I will give a quick synopsis here. It is rare to see “large” gasoline units anymore, but the Honda/Yamaha gas units are pretty popular for the smaller sizes around 3-6KW. Problem with gas of course is that it requires a secondary fuel source that we do not use on the actual apparatus and they require refilling, separate from the apparatus. The little Honda jobs (primarily the 3500 and 5000 watt models, are great devices and offer a nice little package for those who want some power on smaller units for basic lighting and portable usage…..at a NICE price. Quiet, reliable and an awesome little package!

    As far as belt driven units, I would say yes there are a few out there, but they have some restrictive features. One major one I see right now, is that the new emissions requirements continue to plug up the engine compartment and makes it harder and harder each year to put anything else under the hood or doghouse. They do have application, but I would also warn, that some may or may not comply to NFPA guidelines, that did not exist previously and do today. I must emphasize on any post, that NFPA should be utilized as our guide to any installed component. As boring as it is to read, NFPA does help give us some direction and minimal requirements of safety and performance.

    I am going to break my response up into three sections for everyone as to not confuse each type of device we “commonly” use on our trucks. You can blow by the info on the one you do not want also! If I bore you, hit delete and I will not be offended! Here are the websites of several companies I know that produce these devices for fire trucks, I APOLOGIZE to all of those generator people I have not included, as I know there are many good suppliers out there, sorry. These are the ones I know and have used, that are utilized a higher percentage of the time on fire trucks and are household names to me. Please understand when I write, I am only trying to share my own experience and cannot be everything to everybody. Motto and RULE 1: There is an exception to every rule! So, be open-minded! Example: Someone once said: “There is no way an anvil can ever be broken”.... Then....they gave it to a fireman! So I hope I can furnish some helpful information below on each type of device to be considered on your next rig. The opinions are mine and only mine!

    www.harrisonhyragen.com - Hydraulic generators

    www.onan.com – Diesel, PTO and hydraulic generators

    www.a-m-p-s.com – Hydraulic generators

    www.marathonelectric.com – PTO/Split Shaft Generators

    http://www.wincogen.com/ - PTO Generators

    http://www.munciepower.com/main/PTO.htm – Power take offs

    http://www.parker.com/frameless/cm.asp?type=2&cmid=304 – Power take offs

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    Default DIESEL - For those who care...

    DIESEL- Fairly simple stuff. Diesel engine, driving a two bearing alternator in a package from MANY companies. The “majority” in the fire service, are from Onan (yes I know there are MANY other brands). Onan has been supplying mobile generators for fire trucks for an awful long time and they “probably” have the most units in service. I apologize to other manufacturers for not mentioning them!

    Now to toot Onans horn a bit, I will give then the benefit (and ours actually) that there are more service locations here in the U.S. than anybody else I know of. They are owned by Cummins and that makes it pretty easy to get service on a broad basis.

    Diesel is pretty reliable. They do require significant ventilation, vibrate some and run a little hot. The problem here is, we in the American fire service love to make things “pretty”, enclose and box things in. We love to: Put covers on things, hide things, tuck things in, LOL!. Well, with diesel, you cannot or its brain (please use yours, we are in a risky business) will utilize the nice little feature they all have, which is “high temp shut down”, to prevent them from burning up! If you like operating in the light, all the time, DO NOT “box”, “stuff” or “tuck” these in, within reason. I believe in protecting things, but I also like to have things working all the time. So diesel is old school, reliable and a decent power source.

    Downside, service, noise and heat.

    Typical power range in fire trucks, 6-15KW, but the bigger diesel units are size limiting and are quite a chunk of iron over 8 KW.

    Positive attributes; You can shut your truck down and use when the rig is off. But let’s be honest guys, how many time to you shut your rig down? Multi-day Haz-Mat / Command incident, ok I agree, but that is the exception to the rule. I personally watched operations at ground zero and yes, there was an application where it would have been nice to have a bunch of diesel units. Lets not start another thread telling about the year we were on scene for 15 days, I know it happens. Diesel is an overall good device, been around a long time, but does require some service, takes up some space where tools might other wise be carried and produces heat.

    There are others out there such as Kubota, Westerbeke, etc. BUT, I will also refer to the threads that people yell about things “working” or better worded, “NOT” working (nobody yells when thing actually work), keep service in mind and buy a model that you can get fixed on a local basis, not half way across the country!

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    Default PTO Drive - For those who care...

    “PTO” DRIVE AND “SPLIT SHAFT” PTO- These are nothing more than the “alternator” found within the diesel package, but without an engine (for you technical people, yes, I am over simplifying it, but to limit confusion, lets leave it at that). It is a sound device and offers a lot of power for a very reasonable price. KW to dollar ratio, these are great devices. Units are available in a couple different applications and “normally” vary from 12KW to 100KW. “PTO” off the truck transmission, normally found sides or top of the Allison transmission housing. BEWARE! Anybody buying their own chassis – The PTO gear inside the transmission is optional from Allison, that last I knew! And YES, I forgot to do this once! OUCH! BE SURE to order you transmission as a 3060 “P” or a 4060 “P”, as the P, signifies the drive gear inside the transmission. Also BEWARE, some of the bigger pto’s, they will not fit on today’s custom chassis’s without significant modification. Things like spring hangers, suspensions, and cab floors get in the way on some models (usually not a problem, that I know of, on commercial chassis’s). I had a rig that the engineers told me that the pto would not fit on and they said they would have to relocate it. Welllllll ok, but little did they tell me that the floor of the cab would be “arched” which is ridiculous! All things considered, the floor would have been fine if it was “boxed” in a way to provide it without being a trip hazard. So, talk to the manufacturers being considered and they can help with that stuff, so you are not surprised when your truck shows up!

    The “PTO” drive on the transmission and is rated to “X” horsepower, dependent on the model. A rule of thumb, and many manufacturers will tell you differently (Hint- talk to many and learn much), but I have spoken to both Muncie and Chelsea (Parker) and they recommend that the PTO be de-rated 30% for what is called “continuous duty” operations, so do it! This will allow you to run up to “about” 30KW in a PTO application. Yes Yes Yes, I know there are some of you out there running bigger units off pto’s. God bless you! I firmly believe in abiding by manufacturer’s guidelines of the device, not someone who “thinks” they know more and then we all fight about warranty later!

    The alternative to “PTO” is what is called a “split shaft pto” application which requires a gearbox mounted inline of the actual truck driveline. This is, for the sakes of describing easily, just like your midship fire pump installation. Shifts, just like your midship fire pumps (ie: neutral on transmission, shift generator and engage truck transmission into drive). These gearboxes in fire trucks are made by Hale and Waterous, typically. The units are heavy duty and can accommodate BIG loads, for things like Breathing Air Compressors, multiple lighting towers, etc. The largest one I know of in a rescue style design (yes, I know someone will find a BIGGER one, its probably just that guy thing....LOL) is around the 110KW size. YES, that is 110,000 watts! The one I know of with 110KW is in a Saulsbury/International rig for NYC’s NYPD - MALT (too funny, but that stands for , Mother of All Light Trucks…LOL) the unit that is used for major electrical supply in subways, building back up, etc. The other really cool thing about the gearboxes is that drive these can drive multiple components off one gearbox. They are available with drive out puts on each side of the gearbox, so you can run other things such as hydraulic rescue tool systems, air compressors, small pto fire pump, hydraulic winch pumps and much more. So, rule of thumb, “PTO” for you units up to 30KW and there after will be “split-shaft” pto for application ranging “normally from 45-75 KW. Split shaft is great for air supply units with electric compressors!

    Ok, downsides. If the manufacturer of the vehicle does not put a splashguard on in the unit (for you people that live in crappy weather like I do!) road salt can corrode the casing and also the actual alternator, if care is not taken when manufacturer's are installing these units. So demand a protective splashguard. That DID NOT say: “case it in and box it in”! It must be some fetish thing with my own guys! All things that go round and round, make noise and spin, produce heat! But, very little with these types of units. BIGGEST problem, you cannot put these on pumpers, unless you intend to never pump when running your generator (yeah right)! Other than that, I personally say: Great performance for the dollar and reliable service. Maintenance, will vary, but is very limited. The normal user will see little to no service. Heavy users will need to think about pto rebuild over so many hours (it varies by brand, but you would have to run the heck out of it to reach rebuild point!) but the normal department will never have to rebuild the pto. Gearbox drive types, require oil change as recommended by Hale and Waterous. Great benefit, these take up NO compartment space! Gearbox and pto ratios can be bought to run at “lower” rpm’s. NO high speed engagement and there are protection devices to prevent you from damaging the unit if someone does inadvertently, otherwise known as an, oops! Primary usage: Rescues and support units.

    These are not rocket science guys, they are used in the agricultural business extensively and are referred to as “tractor drive” units. These are great units. YES, those in the agricultural business are “farmers”.....sorry, the previous “farmer” comment by someone really bothered me! I give “PTO” drive the thumbs up for rescues and support rigs!

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