What better time to take the gondola to K-1? None, none at all. We do work for the two radio stations that are on the peak of Mount Killington, near Rutland, Vermont. In the summer, usually we can drive up there in a four wheel drive truck. In the winter, the gondola is the way to go. On this day, there was a 48-56 inch base, light north winds and air temperature around 10° F (-12° C) .
This is not my video, I did not have enough memory on my SIM card to film a video and I didn’t bring my expensive camera. However, this is a good example of the ride:
Not a bad way to get to a transmitter site, all things considered.
Ride up to Killington Peak
View from Killington Peak
Transmitter buildings on Killington Peak
View from Killington Peak
Tower from Killington Peak
Killington STL dishes
ERI antenna, WZRT/WJJR Killington VT
The reason for the trip today; repair work on the Nautel VS2.5 transmitter. All three power supplies and the power supply summing board needed to be replaced.
We removed this old Harris BC5HA transmitter recently:
Harris BC5HA, WROW Albany, NY
It was installed new in 1974, when the station moved to this site from another one a few miles up the road. It functioned as a main transmitter until the BE AM5E was installed in late 2001. The BE transmitter, other than a power supply issue, has been a solid, reliable unit. Truth be told, the last time the BC5HA ran was in 2006. After that, the unit refused to run, a bad modulation transformer was suspected. It was deemed not worth it to repair, thus, out the door it goes. We ended up giving it to a local contractor who scrapped the metal in lieu of payment for his labor. The only thing he could not take was the aforementioned modulation transformer, which is full of PCB’s. That will have to be hauled away by a licensed disposal company.
Broadcast Electronics AM5E, WROW Albany, NY
We may be getting a second hand Nautel transmitter from another station as a backup transmitter. If that comes to fruition, then a couple of racks can be added to the end of the Phasor/transmitter/transmitter row and the wiring for the remote control and STL can be simplified and neatened up.
That saying originates from Greek and Roman times, when Sirius, the Dog Star, aligned with the Sun during July and August and was though to bring extra heat to the earth. The Dog Days are evil times; seas boil, wine turns sour, dogs grow mad, and all other creatures become languid; causing to man, among other diseases, burning fevers, hysterics, and phrensies.
Bad news, indeed. Add to that; air conditioners fail, general managers become cranky, transmitters overheat causing damage to sensitive control circuits, which is even worse.
We shall be busy dealing with things like this:
AC condenser frozen dryer and piping
Air conditioning condenser with low refrigerant. This unit either has a leak or was not charged properly. I would hazard the former.
AC condenser broken fan
Fan blade on condenser coil failed due to metal fatigue. I have seen this in more than one place.
Bard 5 ton wall mount AC unit
These wall mount Bard AC units are pretty reliable, however, even they fail from time to time. The best course of action is to have a maintenance plan, a backup plan and the number of the best HVAC contractor that can be found.
I was fortunate enough to acquire this generator last fall. It was new in 1969 and has unknown hours on it, but it appears in decent shape. I am going to do a level two overhaul and install it as backup power for my house/shop. The first order of business is a complete inspection. I discovered a few problems; the starter didn’t crank, the distributor was loose, and the carburetor had some burned out chunk of metal attached to it.
Onan 12JC4R generator
First, the starter: These units use a Prestolite MEO3006 starter, which is common to several Chrysler products from the late ’60s and early ’70s. This is obviously a replacement unit, as it is not “Onan Green.” When I hooked a battery up and tried to turn the motor over, the start relay clicked but nothing else happened. I dismounted the starter and removed the starter solenoid. The interior of the starter motor looked in good condition, which points the solenoid. Sure enough, I removed the back of that unit and found two wires burned through and a large blackened area. While I had the starter off, I hooked it up to a 12 volt battery and it worked fine. A new starter costs $469.00, a new solenoid cost $59.00. I opted for the solenoid.
Onan 12JC4R burned out generator starter solenoid
The next thing is the distributor. I was checking the points and contemplating replacing the breaker points with an electronic ignition when I discovered the distributor could turn 1/8 of a turn in each direction, as when making timing adjustments.
Onan 12JC 4R distributor clamp
I used a 3/8 box wrench and tighten up the clamp holding the distributor shaft. It took several turns and makes me wonder why it was loose. I will have to check the timing with a light once I get it running. This also could be why the generator was not running when we took it out of service.
Onan 12JC 4R rotor and breaker points
As for the points, they look brand new, as does the rotor and distributor cap.
Onan 12JC 4R generator spark plug, champion H8C
The spark plugs look well used and the plug wires look original.
Finally, there was an electric choke mechanism on the carburetor which is completely unnecessary for a propane fueled unit. The choke plate itself was wired open. The electric choke was was burned open, so I removed the assembly. I then spent some time at the local NAPA cross referencing parts. Here is a tune up list:
||Onan part (old)
||Onan part (new)
|Plug wire #1
|Plug wire 2,3,4
|*Electronic ignition set
|**Ignition coil W/PRX 1545
*Condenser and breaker points can be substituted for electronic ignition kit, either Onan 166-0825 or Pertronics 1545 with Pertronics PRX 405011 coil.
**Pertronics electronic ignition must be used with Pertronics coil
***Champion RH8C plugs should be used with replacement wires without noise suppression plug boots.
This is for an Onan 12JC generator circa 1969 with a Studebaker engine. Other models/years may vary. The other issue with this unit is there is no supervisory monitoring and control. There is no oil pressure loss, overheat or overcrank faults. This is why the starter solenoid failed. To remedy that situation, I started to design a better control circuit. Then I looked around on the inner tubes and found somebody had already done this. DynaGen makes the GSC400p which has can monitor oil pressure, engine temperature, frequency, engine RPM, hours, voltage and current. It can fault for any out of tolerance condition, as programmed by the user.
Retrofit generator controller
I plan to install this in the original control box, leaving the original control circuit intact by using the remote start/stop connections. I keep the original remote/start/stop switch and hand crank switch in place for use if the fancy controller fails.
This is a set of burned contactor fingers on a Harris HS-4P 30 amp RF contactor:
Harris HS-4P RF contactor with burned finger stock
The back story is this:
The contactor in question is at the base of Tower #3 of the WBNR (1260 KHz, Beacon, NY) antenna array. This is the tallest of all the towers, at 405 feet. As such, it gets struck by lightning often. There was at least one occasion where one of the inductors in the ATU got “sucked in” due to the huge magnetic field of a high current strike. It is not at all surprising to me to find other component issues in this ATU. Because of the burned contacts, I’d suspect that the station was switching modes under power, but I didn’t see that happening today.
The problem manifested itself in very high SWR after changing over from day pattern to night pattern. This did not occur every time, in fact, it only occurred once in a great while at first. Then, over the last couple of months it began occurring more and more often. Since the snow drifts are now down to a manageable six to eight inches, it was a good day to go out and do some exploring.
First of all, I put the station into night time mode just to confirm that there is still an issue. The transmitter, a Broadcast Electronics AM1A showed very high SWR and carrier fold back. Left it in night pattern, but turned it off and took a walk, not a drive, to Tower #4 which is all the way at the bottom of a hill, near the old City of Beacon landfill. I figured that I would check that one first, then look at Tower #3 on the way back. When I got to Tower #3, I found the issue right away.
Fortunately, I was able to salvage a set of contact and contactor bar from another relay in the same ATU that was not using them.
Burned RF contactor bar
The night pattern is only 400 watts, but these are tall towers, 225 degrees, therefore current and voltage are high at the base. In fact, the slightest change at the base of the night time towers will greatly upset things.
Burned RF contactor fingers
Harris HS-4P contactor repaired
This is the repaired contactor. I will say, the EF Johnson RF contactors are easier to work on. Those are the ones with the big rocker bar across the top and two solenoids on either side. All of the wiring, status switches and contacts are exposed and easy to get to. This one, not so much. This is the BE AM1A transmitter
Broadcast Electronics AM1A transmitter
It is not a bad unit, compact, sounds good, reliable, etc. In order to work on the power supply or anything in that top cabinet, the whole thing needs to be removed from the rack and taken down. I suppose that is my only gripe about the thing.
The WICC transmitter site, Pleasure Beach in Bridgeport, has been cut off from normal access since the bridge to the island burned in 1996. Since that time, access has been by boat with a 0.93 mile walk from the dock to the transmitter building.
Last summer, LVI Construction, under contract from the Town of Stratford, put in a temporary road and began removing the burned out cottages. While that road is in place, the radio station has been able to access the site and get many important things accomplished. These include:
- Replacing the vandal damaged top beacon on the South tower
- Removing several decades worth of stored crap, garbage, obsolete and unused equipment
- Repair the electrical service to the building
- Replace the generator transfer switch
- Repair the Sonitrol building alarm
- Replace the old Onan Generator
- Have the power company replace the 3 phase circuit from the point where the under water cables come ashore to the transmitter building.
All of these projects should greatly improve the reliability of the station. This should make Bill, happy, who appears to have a WICC chip implanted in his brain because every time the carrier is interrupted he posts about it on the radio-info.com website.
The biggest issue with the site was the utility feed from the shore to the transmitter building. The original circuit was installed in 1936 when the station moved to the island. It was old and the poles were all rotting and had horizontal cross arms. Ospreys especially like the horizontal cross arms as they made good nesting spots. That is, until the nest shorts out one of the phases catches on fire and burns the top of the pole off. This has happened several times over the years causing many hours of off air time.
WICC new utility service
United Illuminating, the local utility company, was very cooperative and installed new utility poles, wires, breakers and transformers, this time with a vertical phase arrangement, which should keep the Ospreys off of them. Additionally, the cottage removal project included installing Osprey nesting poles.
Pleasure beach cottages removed
With almost all of the cottages now removed, the area looks much better than before. Actually, it should be a nice nature preserve and hopefully, the absence of the buildings might reduce the number of vandals in the area. The work is almost done, so the road is about to be taken up. This means we need to wrap up the work out there, so the final push is on.
WICC transmitter building
In the last three weeks, 10 truck loads of junk have been hauled out of the transmitter building and generator shack. Over 1,500 pounds of scrap steel, 640 pounds of insulated wire, 2,000 pounds of particle board furniture, old t-shirts and hats (something called “Taste of Bridgeport” which, if anyone knows what that was let me know), old propane tanks, batteries, etc. We also managed to fix the fence and gate in front of the building, cut down the over grown yew bushes and bittersweet vines.
The old Kolher transfer switch was also an issue. There was no place to mount a new switch inside and mounting one outside is out of the question, so the guts from the Kohler switch were removed and replace with an ASCO unit. This was done in the summer of 2009. The breaker on the right side is the main service disconnect for the building, which was installed in September.
Onan 12 KW 12JC 4R air cooled generator, removed from service
Today, it was time to replace the Onan propane generator. The old generator is an Onan 12JC-4R air cooled propane unit which was installed on April 4, 1969 at a cost of $1,545.00 new. For many years, this unit gave reliable service, but it has many, many hours on it and it lacks the fault/self control circuits needed for remote (read desolate) operation. Several times over the last few years, the generator would run out of gas or the propane tank would freeze up and the starter would crank until it burned out.
It was cold out on the island, with temperatures in the twenties and a bitter west wind blowing right into the generator shack. All of this conspired to make working conditions difficult. Wind chill readings were in the single digits all day long, and in spite of long johns and extra layers, by 3 pm I was shivering and even several hours after coming inside, I still feel cold.
Using tractor to move new generator
The new generator is an Cummins/Onan 20GGMA which is rated for 20 KW. We used a John Deere bucket tractor to move the generator from the flat bed truck to the generator building, then push it inside. The old generator wiring to the transfer switch was reused, but a piece of flex was used to connect to the generator instead of the solid conduit. The building fan was also wired up so that it will run whenever the generator is running.
The generator load with all possible things switched on and the transmitter running at full power is about 12,000 watts, but this would mean the air conditioner and tower lights were on during the daytime. More likely, the transmitter will be at low power when the tower lights are on and the AC will be intermittent on/off at night. At full load, this generator uses slightly less than 2 gallons of propane per hour. At half load, I’d estimate that to be 1.4 or so gallons.
Cummins Onan generator in new home
100 pound propane gas tanks
HOCON gas came out and connected six 100 pound propane tanks in series, which should prevent tank icing. Propane weights about 4.11 pounds per gallon, therefore the fuel supply should last about 100 hours, or 4.5 days, give or take. Why 100 pound tanks? Because we will have to shuffle them back and forth between the dock and the generator shed, a journey of about one mile, in a cart. Anything larger would be impossible to deal with. Even so, refilling the propane will be a 2 person job and will likely take all day.
Back in the day, when tube transmitters ruled the broadcast world, common practice was to have a big cooling fan moving outside air through the transmitter building connected to a thermostat. Temperature swings of 30 to 40 degrees were common, however, the tube rigs could handle almost any temperature that didn’t melt plastic or freeze water.
Today’s solid state transmitters are not that rugged. They like to have there rooms around 70 degrees +/- 10 degrees or so. Not to mention the other computer controlled equipment commonly found at a transmitter site. Things like air chain processors, STLs, remote controls, etc. So, lots of air conditioning is the norm, and with lots of air conditioning comes lots of maintenance.
Air handler air filters need to be checked and replaced often. Condenser coils seem to attract every type of flying debris on the planet and need to be cleaned once, possible twice per year depending on tree and weed species near the site. Even with the preventative maintenance, occasionally things like this happen:
AC condenser frozen dryer and piping
Of course, the entire cooling coil inside is frozen solid.
This condenser is low on refrigerant, causing icing problems. It has a slow leak somewhere and is about to be replaced. Other reasons for this happening are malfunctioning or non-existent low ambient kit on the condenser fan. Sometimes less than knowledgeable persons will install a 5 ton unit designed to run throughout the year but not take into account the effect of moving below freezing air at high speed across the coils. Insufficient air moving across the cooling coil will also cause this. Insufficient air flow can be due to plugged air filters or clogged fan/blower blades.
This one is even better (same condenser unit):
AC condenser broken fan
The fan blade is sheared off and jammed into the condenser coil. This happened during power transfer from generator power to commercial power. Naturally, it was at 1 am in the morning after a pole mounted transformer had been replaced. When the building transfered back to commercial power, I went outside to use the “bathroom” before my two hour drive back home. I though I smelled something hot, you know that cooked paint/plastic smell, but couldn’t really track it down… the winds were kicking up and another thunderstorm was on the way.
The next afternoon, however, when the sun was up and the site was working on one air conditioner, the temperature alarm went off. Upon arrival, I found the condenser breaker tripped, resetting it caused the building lights to dim. The fan motor was shorted to case. I would theorize the aluminum fan blade suffered from metal fatigue, likely because the blades were not balanced causing a vibration. When the power transfer occurred, there was just the right combination of torque and centripetal force to cause the blade to rip, then lodge in the condenser coil.
The fan motor has replaced, but I think it is time to replace the whole condenser unit, which will be expensive.
AC&R Gauge set
I found having a set of gauges to check the head pressure and suction is a good diagnostic tool to quickly pinpoint problems with HVAC units. This way, when the HVAC tech shows up, you can quickly point him in the right direction.
This is yet another addition of the “Burned up Sh*t” collection:
GE 30 Amp 3 pole breaker
It is a breaker from a 5 ton AC compressor. Back in the bad old days when I was the Director of Engineering for a 28 station group Headquartered in Harrisburg, PA, I received a phone call from one of the local engineers. He stated that the studio AC unit compressor had burned out again and the breaker keeps tripping. What did I think, asked he. I thought perhaps he should dig a little deeper and determine why the breaker was tripping before throwing another AC compressor at it. When are you coming to town again, he cheerfully inquired.
Okay, I get it.
I started by calling the HVAC company to inquire what had gone wrong with the compressors. Winding shorted to case for both units was the answer received. It being July and mighty hot out, the various worker bees in the studio where feeling inconvenienced by the sweat in their eyes and dripping on their work, etc. I called the local manager and asked for a hotel room, I’d be up tomorrow. Then I called the HVAC guy back and asked in to meet me at the studio tomorrow afternoon.
Upon arrival the next morning, I found the fifth floor studios to be hot, as reported. I trip to the roof location proved to be hotter still. I tested the voltages at the compressor unit with a DVM and everything looked good. A trip down to the utility room found the electrical panel in reasonable shape. Then the local engineering guy chimed in, “Oh yeah, I forgot to tell you, the breaker hums and gets hot when the compressor is on.”
It’s always that little bit of missing information…
I took the breaker out and sure enough, the fingers were all arched and nasty looking.
I replaced the breaker, the HVAC guy showed up, with a new compressor and the studios began to cool off around 3 pm.
Since then, I specify Square D QO bolt on breakers for new installations, especially for heavy loads like AC units, transmitters, and so on. They are a little more expensive, but in the light two AC compressors, the unscheduled trip out of town, and the grumbling staff, it is better to pay upfront for better equipment than to put up with preventable outages.
File under some new everyday. Yesterday, there was an area wide power outage in Woodstock, NY. The backup generator failed to start, however, WDST remained on the air until the UPS batteries ran out several hours later. Then my cellphone rang. Alas, yet another Sunday on the job.
Upon arrival, I found the power had just come back on, so the DJ (yes, there was a live person in the studio, on Sunday) was restarting the NextGen system and getting the station back on the air. I restarted the rest of the servers, streaming computers and what not. While I was there, I figured I might as well see why the generator didn’t run.
Pressing the start switch led to the “click, click, click, click…” which normally indicates the battery is dead. Deciding that I should dig a little deeper, I got the volt meter out. Battery voltage, no load 13.8 volts. A normal reading. Flick the starter switch and measure the battery voltage again, under load 13.7 volts. Hmmmm, now that is not what I suspected. If the battery were bad, the voltage should drop down under load.
Cracked Battery Terminal
I grabbed the negative cable and it came off in my hand. Another one of those “ah ha!” moments. Upon closer examination, the terminal connector is cracked in half.
Cracked Battery Terminal
I went to the local Ford dealership and bought a heavy duty truck battery cable. Since the battery itself is six years old, I decided to bring it and have it checked, and sure enough, the battery was going bad too. Rather than suffer through another power outage without generator, I went ahead and replaced the battery.
Why the terminal cracked in half in the first place, I don’t know. Perhaps it was over tightened, or some type of manufacturing defect.
Broadcasters historically have tried to remain on the air during emergency events like major storms, earthquakes and other forces of nature. Often times, commercial power is interrupted, and thus, the backup power generator is installed. Propane powered generators for medium duty (powers up to 45 KW) are popular because of the decreased environmental hazards, availability and expense of fuel, ease of maintenance and repair. This sized generator can run the critical loads of a studio facility or a transmitter site with TPO’s between 5 and 10 KW.
Katolight 45 KW generator w/outside housing
Most propane generators use a gasoline engine modified to use propane. These generators can also use natural gas, however, because natural gas has slightly less energy, the generator’s service rating is reduced by about 10 percent.
Ford inline 6 cylinder engine
The biggest error I consistently see with propane generators is improper fuel tank sizing. It might seem just fine to plop a 500 gallon tank down next to a 45 KW generator and expect everything to be just fine. 500 Gallons may sound like a lot of fuel, but the more important consideration is tank vaporization, that is to say, how fast can the liquid propane can be removed from the tank for use. Propane fuel companies should be able to sizing these things correctly, most of them have books and charts that tell what capacities and sizes are needed. However, as a general trouble shoot guide, the following information is provided:
Generator manufactures will specify how many BTU per hour a generator will require under full load. If not, these are some conservative rules of thumb:
- For every 1 KW of electrical generation, 2 horsepower of engine is needed*
- Under full load, each horsepower will consume 10,000 BTU per hour*
- Propane has 92,000 BTU per gallon
- Propane weighs 4.2 pounds per gallon
*Note: These are not the figures you will find in your engineering handbooks, they are adjusted for generator winding and engine efficiency.
Propane Tank Vaporization Rates (Continuous BTU/hr vs volume at tank temperature):
|Size propane in a tank (assumes 1/3 full)
||Maximum continuous BTU/hr at degrees F
Note: Tank vaporization depends on fuel level, tank temperature and withdrawal rate. The above chart is a conservative generalization and represents a safe median value.
If a propane tank cannot vaporize fuel fast enough, the generator will begin to run lean, eventually overheat and shutdown. The vaporization rate depends on the tank temperature, which drops as fuel is withdrawn. For the above cited 45 KW generator called to duty after a sever winter storm, the tank would need to vaporize: 45KW x 2 HP = 90 HP. 90 HP x 10,000 BTU/hr = 900,000 btu/hr. A 500 gallon tank is too small for that size generator.
As the tank temperature drops a propane tank can develop frost on the outside of the tank, even on a hot summer day, which compounds the problem.
The correct size tank for a 45 KW generator is a 1000 gallons. This can also be two five hundred gallon tanks connected in parallel via a high pressure line.
45 KW propane generator with two 500 gallon tanks
Also note, the generator’s radiator is facing the tanks so that when the unit is running, hot air is blowing on the tanks, warming them up. This particular generator is about 25 years old, which is why it looks a little worn. It still carries the load and mechanically is in sound condition.
Most propane fuel systems have two regulators; one high pressure regulator on the tank, which takes the variable tank pressure and steps it down to about 10 PSI, and the vaporizor which steps the pressure down to a few ounces per square inch (or inches water column) and adds air creating propane gas for the generator to burn.
High pressure propane tank regulator
It is important that the vaporizer be mounted above the snow line and that there is a little screen on the air intake, otherwise mud wasps will build a nest in the air intake and the next time the generator is required to run, it won’t start.
Low pressure propane regulator/vaporizer
Fuel piping is also a concern, if the low pressure lines are not large enough to handle the required BTU, the generator will run lean, creating the same problems of an improperly sized tank. Different piping has different capacities, see the following charts:
Propane Schedule 40 steel pipe sizing diagram
Propane copper-K pipe sizing diagram
Assumes pressure less than 1.5 PSI, one MBTU is equal to 1,000 BTU per hour.
Once the generator is installed, maintenance is required. As a minimum:
- Exercise engine bi weekly for 15 minutes. Propane generators do not need to run under load.
- Check fuel, oil, and antifreeze levels monthly, more often if heavy use.
- Change the oil, oil filter, air filter, check antifreeze freeze point, battery electrolyte specific gravity yearly
- Change out belts and hoses as needed, pay close attention to the block heater hose, this is where leaks often develop
- Clean out mice nests and droppings as needed
Mice love generators.