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Standby generator opinions

rfburns

rfburns

One of my clients is looking into a 125 kw propane generator setup for their transmitter site, and I'm getting quotes now. One of the best (cheapest) quotes so far is from a company that handles Generac products. From what I've heard, I would be better off to stay away from a 125 kw Generac setup for a 50kw AM site, but I really don't have any first-hand experience with any generators that size. Anyone have opinions (good or bad) on what to look for?

RFB
 
> One of my clients is looking into a 125 kw propane generator
> setup for their transmitter site, and I'm getting quotes
> now. One of the best (cheapest) quotes so far is from a
> company that handles Generac products. From what I've
> heard, I would be better off to stay away from a 125 kw
> Generac setup for a 50kw AM site, but I really don't have
> any first-hand experience with any generators that size.
> Anyone have opinions (good or bad) on what to look for?
>
> RFB
>

First a word about fuels. Is your site located in a climate with cold winters? If so, I would tend to stay away from a propane powered plant because they can be tempramental in the winter. Propane doesn't like to evaporate inside the tank during really cold wx which can lead to low pressure and hard starting.

Many of the wireless carriers around here seem to like the Generac diesel plants but I have had the best experience over the years (with plants in the 15 to 250 kW range) with Kohler and Onan diesel powered units. Another excellent choice might be a CAT diesel plant. You will find a lot of them in service as primary power sources for remote facilitiesaround the world.
 
> > One of my clients is looking into a 125 kw propane
> generator
> > setup for their transmitter site, and I'm getting quotes
> > now. One of the best (cheapest) quotes so far is from a
> > company that handles Generac products. From what I've
> > heard, I would be better off to stay away from a 125 kw
> > Generac setup for a 50kw AM site, but I really don't have
> > any first-hand experience with any generators that size.
> > Anyone have opinions (good or bad) on what to look for?
> >
> > RFB
> >
>
> First a word about fuels. Is your site located in a
> climate with cold winters? If so, I would tend to stay away
> from a propane powered plant because they can be
> tempramental in the winter. Propane doesn't like to
> evaporate inside the tank during really cold wx which can
> lead to low pressure and hard starting.
>
> Many of the wireless carriers around here seem to like the
> Generac diesel plants but I have had the best experience
> over the years (with plants in the 15 to 250 kW range) with
> Kohler and Onan diesel powered units. Another excellent
> choice might be a CAT diesel plant. You will find a lot of
> them in service as primary power sources for remote
> facilitiesaround the world.
>

Everything else aside, Generac is a local (for me) company. I've been to their plant and have worked with their people on several occasions. I've been very impressed with them.

That aside, I also have Kohler and Onan units, and they've been great.<P ID="signature">______________
</P>
 
> > > One of my clients is looking into a 125 kw propane
> > generator
> > > setup for their transmitter site, and I'm getting quotes
>
> > > now.

Like was said above about climate and such - maybe check what your local telcos are using at their sites. I would think they would have the type that would give the best results, fuel type and brand.

EN
 
> One of my clients is looking into a 125 kw propane generator
> setup for their transmitter site, and I'm getting quotes
> now. One of the best (cheapest) quotes so far is from a
> company that handles Generac products. From what I've
> heard, I would be better off to stay away from a 125 kw
> Generac setup for a 50kw AM site, but I really don't have
> any first-hand experience with any generators that size.
> Anyone have opinions (good or bad) on what to look for?
>
> RFB
>
I've always been told to stay away from Generac.
Around my parts, the Olympian and Onan are the two sets most of the big guys use. I run an Olympian 100Kw natural gas setup. It can easily be backed up with propane but I'm a college station so what's the point!
BTW, 125 Kw seems small for a 50Kw AM.....even with 86% AC/RF efficiency on a DX50. With 125%- 150% modulation the draw will be quite a bit more.....but, then, I guess it's not ALWAYS pulling the power.... but your average draw would still be pretty high.
Is that the standard set size for a 50Kw AM site?
 
The site I do work for has two 350kW CAT units that are very reliable, except for, when it comes to ordering parts.

In live vehicles I have played with Kohler , Onan, and Generac.

So far the Kohler's were pretty beaten up and still worked.
The Generac is a P.O.J. It always seems to be failing for one reason or another. We've replaced two stators on it, bushings, and several parts. In fact, even though it is five years old, we are considering a full out replacement.

The two new live vehicles have ONAN's and they have been fantastic. Quiet and reliable. Very few problems.

Now I know several buildings Ive been to with Generac generators that absolutley love them but from personal experience, I'd never buy one.
 
>>
Generator FUN.

Size all natural gas and propane generators are de-rated from their diesel cousins.

WE are running a 250 KW Cummins/Onan diesel generator oversized 200 KW would be sufficient.

Propane in cold weather needs a large size tank in order to vaporize, this can be a building department problem.

Natural gas is interruptible service (when the lights go out the gas may stop as well)

Diesel fuel goes BAD. It must be used or stabilized.

Diesel generators need block heaters that run 4kw and are needed 12 months a year in New York (yes they have a thermostat).

We have a Genrac 35 KW generator for our studio; it runs on a Mazda truck engine. It sits over its fuel tank, 136 gallons. Nice, but too small package because it will not run the studio AC units proper size should include everything you have running during an emergency.

FUEL supply, what ever you use needs to be replenished, can you run a few days?

Maintenance a service contract, quarterly inspections, load testing are all non capital expenses.

UPS SUPPLIES your studio and essential (computers) need to be on UPS preferable dual convergent units with voltage regulators on the input. Dual convergent units mean the battery charger constantly charges the battery, the inverter runs constantly manufacturing the conditioned regulated AC power.

Caterpillar markets a neat Motor generator set that completes isolates the station from the public utility and the generator. There is a flywheel in a vacuum that provides 30 seconds of power until the generator starts. This is very expensive.
 
Not mentioned yet about the Generac is the lousy power that they put out. Lots of stray spikes in the waveform. Never could get any UPS to like a Generac with a load above 50%. With the Generac suppling power the UPS's stay on battery untill the quit! With all the switching supplies on the load the power factor goes to h***. It been told to me many time it's a real good idea to oversize the genset/keep the load below 75%.
 
> Natural gas is interruptible service (when the lights go out
> the gas may stop as well)

Nope...NG will stay flowing even when the lights go out...even after hurricanes, etc, the gas keeps flowing....its all pressure and doesnt require power in the immediate area...It is only required at a compressor station..which is many miles away from a city gate..
If you can get NG at the site, its best to go with that over anything else.
 
> Not mentioned yet about the Generac is the lousy power that
> they put out. Lots of stray spikes in the waveform. Never
> could get any UPS to like a Generac with a load above 50%.
> With the Generac suppling power the UPS's stay on battery
> untill the quit! With all the switching supplies on the load
> the power factor goes to h***. It been told to me many time
> it's a real good idea to oversize the genset/keep the load
> below 75%.
>

Stay with Kohler or CAT.. You won't be dissapointed. If your going desiel, I'd say CAT would be the absolute best. I have experience with both of them, and the CAT desiel we've got is old as hell and the MOST reliable of the whole bunch. For ease of use and not having to mess with enviromental issues or keeping good fuel and the tanks, I'd go with natural gas if you have pipes big enough to deliver it to your plant. Keep in mind that normal natural gas lines in many cases aren't big enough to supply enough gas to run larger generators, so be sure to check to see if the line running to your transmitter site is big enough or how much it will cost to have a larger line ran to do the job. I love going with natural gas as they are much cleaner, much less B.S. to keep going, and just generally easier to deal with. Pay the gas bill, make sure you have oil and water in it, and make sure the battery works. Pull the rip-cord once a week to make sure it works, and you're golden. In my humble opinion all "contract" radio stations should try to get natural gas gensets as they require a lot less attention to keep them keeping you on the air. A modern Kohler natural gas unit would be my choice if going that route.


<P ID="signature">______________
--- THE Insultant ---</P>
 
Fuel:

I've used gasoline, propane and diesel over the years.

The diesels have proven most reliable and most durable but there are tricks to it. Right now I'm sitting inside a station in Nome, Alaska where I installed two new diesels about 8 years ago. Both are John Deere engines with the generators and control installed by a third party and sold by Northern Lights out of Anchorage. They sit idle for months at a time and then may have to run for two continuous weeks, depending on storms.

Temperatures here commonly run -20 to -30 degrees. One 55 KVA is in a heated building next to the studio. Kept at about 50-degrees with a stick-on heater on the oil pan. The transfer switch runs it (unloaded) for about 20-minutes once a week. The one at the AM site 25-kW Nautel, ND) is 66 KVA, three phase. It's in an isolated building (fire protection) about 40-feet from the transmitter building. A small electric heater keeps the building between 45 and 50 degres. Air intake vents are motorized; a small one opens whenever the generator runs (for combustion and limited cooling air). A second, much larger motorized louvre is controlled by a thermostate to keep things cool when needed (rarely). When I was here full-time I ran it for an hour a week. Now it's lucky to get run once a month.

Fuel is #1 fuel oil, NOT diesel. Because #1 is very "dry" with little lubricating value, we add a product called "Hot" which is a little bit anti-icing but, more importantly, adds the missing lubrication. If you're dealing with any kind of cold, avoid #2 fuel or common diesel fuel. It gums up too quickly, is slow to vaporize, and will congeal without warning.

Whatever battery starting capacity is recommended, double it. I use little "battery minders" to keep 'em up. Change batteries by the calendar, not by performance. Cheaper to replace them at half their stated service life than have one fail to fire up when the snow is horizontal, the wind is 50 MPH and the temperature is -20.

All-in-all, based on experience, I can't recommend anything other than diesel.

Oh....

MOST IMPORTANT

Studio site generators are running more computers than audio gear. To prevent ping-pong UPS effects, size your generator at least double what you think you need; better THREE times larger. Spend the extra money for precise frequency control, precision regulation, and permanent magnet excitation. If your proposed vendor has never heard of those things and/or can't offer them, find a NEW vendor immediately. Transmitter generators are generally less demanding but, as those sites get more computerized, think hard about capacity!<P ID="signature">______________
When you're done impeaching the prez, keep on going; recall every member of congress and lock 'em up! Let's try NO govt. for a while.</P>
 
> Caterpillar markets a neat Motor generator set that
> completes isolates the station from the public utility and
> the generator. There is a flywheel in a vacuum that provides
> 30 seconds of power until the generator starts. This is very
> expensive.

That unit is built by Active Power in Austin, TX. If you get to Austin, you should visit their factory. It is really impressive.

They build an amazing device, but as you said, it is really expensive.
 
> I'm not so sure about that.
>
> Natural gas fuel sources represent a cleaner alternative
> compared to liquid fuels, but like liquid fuels, natural gas
> has its advantages and disadvantages. Not all enterprises
> have access to gas fuel utility services, for example. Also,
> gas utility supplies share similar outage risks with
> electric power. "These generators are cleaner than diesel
> but also take a bit longer to start and would have to be
> used in conjunction with a UPS," Info-Tech's Armstrong says.
> "Also, gas must be piped in, which could cause problems,
> depending on the reason for the electrical outage."
>
> R
>
> > Nope...NG will stay flowing even when the lights go out...


Our studio genny is on NG and we have never had a problem running on it when the power is out (knock on wood). With that said, I tried to get the bean counters to get a propane tank next to the genny in the event the NG stopped, we could flip over to the propane (I know we would have to do a minimum of work). Now, this is no sh*t, I was told it would cost to much to convert our genny from diesel to propane...trying to explain that our transmitter sites were diesel and the studio was on NG fell on deaf ears.
G
 
> I'm not so sure about that.
>
> Natural gas fuel sources represent a cleaner alternative
> compared to liquid fuels, but like liquid fuels, natural gas
> has its advantages and disadvantages. Not all enterprises
> have access to gas fuel utility services, for example. Also,
> gas utility supplies share similar outage risks with
> electric power. "These generators are cleaner than diesel
> but also take a bit longer to start and would have to be
> used in conjunction with a UPS," Info-Tech's Armstrong says.
> "Also, gas must be piped in, which could cause problems,
> depending on the reason for the electrical outage."
>

I am sure...I have worked for a NG company (and an electric utility too)...I saw what happened in Katrina, Rita, and others....the NG kept flowing...the leaks were the biggest problem for the service techs to do...(flooding contaminates the gas piping so the gas is left on to flow to prevent back feed) and gas IS piped in...with the majority of the transmission/distribution being underground, kinda hard to get damaged in a hurricane.
 
> > I'm not so sure about that.
> >
> > Natural gas fuel sources represent a cleaner alternative
> > compared to liquid fuels, but like liquid fuels, natural
> gas
> > has its advantages and disadvantages. Not all enterprises
> > have access to gas fuel utility services, for example.
> Also,
> > gas utility supplies share similar outage risks with
> > electric power. "These generators are cleaner than diesel
> > but also take a bit longer to start and would have to be
> > used in conjunction with a UPS," Info-Tech's Armstrong
> says.
> > "Also, gas must be piped in, which could cause problems,
> > depending on the reason for the electrical outage."
> >
> > R
> >
> > > Nope...NG will stay flowing even when the lights go
> out...
>
>
> Our studio genny is on NG and we have never had a problem
> running on it when the power is out (knock on wood). With
> that said, I tried to get the bean counters to get a propane
> tank next to the genny in the event the NG stopped, we could
> flip over to the propane (I know we would have to do a
> minimum of work). Now, this is no sh*t, I was told it would
> cost to much to convert our genny from diesel to
> propane...trying to explain that our transmitter sites were
> diesel and the studio was on NG fell on deaf ears.
> G
>

We have a natural gas generator. We have NEVER had a outage of NG in the 15+ years that unit has been there. We've had tons of tornados, power outtages, and other fun things roll through Oklahoma. Even when we could smell natural gas blowing up from Midwest City/ Del City in the first Moore F-oh-my-God! tornado several years ago that knocked out lots of homes down there, we didn't have any interruption. The only interruption that occured is to the localized neighborhood areas affected. NG is extremely reliable. To be perfectly safe, haveing propane available in the event of being cut off of gas would be smart, however, don't let that stop you from going with the best way to keep your stations running with the least amount of hassle. Trust me... Buy a natural gas generator and you'll be happy with your purchase.

<P ID="signature">______________
--- THE Insultant ---</P>
 
Katolight, CAT (or Olympian for smaller sets), Onan. Nothing else.

The Generacs are miserable rustbuckets. I will never buy one again. It's just small mistakes like not using quality hardware. The last one I had required some item to be jiggled every now and then to get it to start, and this was only after a few years in a mild environment. I've also had bad luck with Kohlers.

If you're in a rural environment, try to build up a concrete platform two feet high to support the generator. (I'd have a structural engineer spec it) I've seen too many sets with mice nesting in them for the warmth of the heater. It can turn the set into a disgusting mess or even worse, mice will chew the control wiring.

Get an appropriate package of instrumentation. You need oil pressure, water temp, battery voltage, battery charge current, generator volts, generator amps, frequency/tach, and an hourmeter.

Have a generator run alarm on your remote control. It's never nice to find out you were on generator only when the fuel supply runs out. Replace the batteries as a scheduled maintenance item. There was a great Workbench article in Radio World some time ago about the dangers of sealed/maintenance free batteries -- they can be an explosion hazard. Maybe better not to use them.
 
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