Upkeep of apparatus for lengthy life
Also use Cal-Blue Plus to detect slow nitrogen leaks
Fig. 1: WNIS recently kept this unit running for 38 hours.
David Morgan, CBRE, is the Technical Director at Sinclair TeleCable-Norfolk, Virginia. He enjoys the generator tips that we share.
In addition to checking the radiator hoses, check the belts on the engine pulleys.
He sent pictures of the emergency generator at WNIS (AM) 790 in Norfolk. It’s a GM Diesel (from Detroit) Model 4-71. The gray part of the electric generator was replaced in 2003 after the old part was destroyed during Hurricane Isabel itself.
David reminds us the importance of checking the radiator hoses at the top of Fig 2 and checking the belts that connect the motor pulleys together.
First turn off the generator so it doesn’t start while you inspect it. Then gently squeeze the hoses together. They should bend and there should be no visible cracks in the rubber during the bending.
Visually inspect the belts before restarting the generator. (A strong clutter light will help with this inspection.)
Find the longest unsupported section of the belt and inspect it for unusual wear, such as: B. Glazing on the side of the belt or missing parts of the belt. The latter can be caused by high temperatures from the heat of the engine or friction due to belt slip.
Next, start the generator and listen. Noise is the first indication of a problem with the belt (and possibly the pulley). The squeaking of the belt during the start-up process means it is slipping. Check the belt for glazed sides. Also, watch out for squeaks during a stress test as the station’s electrical load is transferred to the generator. Under normal conditions, changes in speed should not cause the belt to slip.
With the engine running, watch out for irregular movements or fluttering of the belt when turning. Both require a further inspection by a generator technician.
As with a car tire, the belt wears out due to friction between the belt and pulleys. The most common area of wear and tear is on the tops and walls of the belt ribs. This friction eventually causes the grooves of the pulleys to rest on the grooves of the belt, causing the belt to slip.
Poor alignment with the belt and pulleys is the main cause of noise. This condition can also cause the belt to fray and premature wear.
The best way to check this condition is to look the side of the belt down to make sure the belt edge is not making any bends away or towards the motor. Any deviation that you can see with your eye is too big.
Another maintenance tip involves using caution when adding oil or coolant to the generator motor. If either of the two comes into contact with the belt, the slip can increase and the slip can cause even higher frictional temperatures, resulting in more belt damage. Also check the seals around the water pump and engine oil seals. Leaks can contaminate the belt surface.
These belt squeak tips also apply to air conditioners. If you hear a squeak, investigate!
Slow leak finder
David concludes his comments by stating that this generator recently powered the station for about 38 hours after tropical storm Isaias blew through the Norfolk area. Even older generators can provide long and reliable service if properly maintained.
David adds a comment on using soapy water to detect leaks in transmission lines and their associated manifolds and nitrogen tank connections.
To detect difficult or very slow leaks, he found it easier to use a blue leak detector spray such as the brand Cal-Blue Plus from Nu-Calgon (www.nucalgon.com), which is designed for HVAC technicians to detect refrigerant leaks detect.
Fig. 3: Cal-Blue Plus remains really sticky for a while after spraying. This makes it easier to spot difficult or very slow leaks.
Unlike bubble water, this spray stays very sticky for some time after spraying. The adhesion allows slowly escaping nitrogen to escape. And because of its high viscosity, the bubbles last a long time. The viscosity also allows the product to stay in contact with the applied surface for an extended period of time, making slow leaks easier to spot.
Cal-Blue Plus is non-corrosive to metal, which means that fittings and copper pipes will not be damaged by the connection. You can find it in places like Grainger and Home Depot, or through Amazon.
John Bisset has spent more than 50 years in the broadcast industry and is in his 31st year writing workbench. He takes care of the sales of western US radios for the Telos Alliance. He is CPBE certified by the Society of Broadcast Engineers and has already received the SBE Educator of the Year Award. Workbench submissions are recommended, qualify for SBE recertification, and can be emailed to firstname.lastname@example.org.
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