Cleaning Generator Slip Rings and Brushes – Part 19

The majority of modern RV generators utilize slip rings and carbon/graphite brushes to transmit magnetizing power to the generator rotor coils. This current/voltage signal comes from the control circuit during starting and the voltage regulator during operation. Read more  Read More →

Troubleshooting Generator Controls Part 18b

Troubleshooting the control system in your RV generator looks and sounds complicated. It can be if you look at the total system concept. It is fairly simple if you look at the board and the system as a collection of simple circuits. Read more  Read More →

Troubleshooting – RV Generators – Part 18a

Troubleshooting an RV generator set requires that you think like Sherlock Holmes and ‘deduce’ things so, get your hat, curved pipe (and maybe a beer) and we’ll see what we can do. First, your generator has to have a problem. The first great rule is “If it ain’t broke, don’t fix it”. If it is broke, then we get to play around and scatter parts all over the lawn. Use your senses to help with the problem. Sight, smell, hearing, touching, etc: Troubleshooting is greatly facilitated if you have the service/overhaul manual for your generator. They are available from the manufacturer, a local dealer or on the internet. The second great rule is “Read (and understand) the book”. The third rule of T-shooting is “determining what type of problem you have”. Ie: Don’t replace the fuel pump if you have forgotten to install the battery. You will troubleshoot differently for operational, mechanical, electrical, or fuel problems. That being said, the majority of T-shooting should be done on a Go/No Go basis. That means picking a point in a system and determining if you have the correct parameter or not. Lets take a common problem and see if we can troubleshoot it. The engine cranks but won’t start. It ran yesterday at the wilderness campsite, so there is a problem. Remove one spark plug and reconnect the plug to its wire. Crank the genset – SEE sparks?? Yes/No – YES. So it is probably something else. Sniff the spark plug area – SMELL gas?? Yes/No – NO. Aha, a... Read more

RV Generator Charging Systems – Part 17

Most built-in RV generators don’t have much of a battery charging system. They normally output only enough DC to run their own subsystems with an amp or two left over. In the 1980’s, most built-in generators had a 5 amp nominal charging system. With coaches having converters and “Smart Chargers’ in them, the generator manufacturers have dropped the genset internal charging systems. ONAN’s Quiet Diesel series has an option of the installation of a 10 amp charging system but it must be ordered with the generator set or it costs $$$ to get it installed later. The larger motor coaches with constant speed diesel generators usually have an automotive type alternator as part of the genset. This alternator will charge any battery/s connected to the genset. The inverter generators normally have charging systems built into them but, if connected to an RV, the ‘Smart’ converter/charger in the coach will charge batteries at a much faster and safer rate. I would only use the inverter chargers for an emergency charging of the truck, car or lawn mower batteries. The contractor type gensets have the capability of running a household or light commercial level battery charger. They don’t normally have separate charging regulators and DC power windings. For those of you with dual battery systems. If you’re driving down the road and the main engine alternator goes out. Start the generator (on its batteries) and then turn on the ‘emergency start switch’ (or whatever your... Read more

Engine oil systems – Part 16

RV generator engines are built with one of two oil systems. The smaller ones generally have splash systems and the larger engines will have pressurized systems. The splash system works by whipping the oil with some sort of an agitator and splashing it all over the inside of the engine. Sooner or later all parts of the engine will get lubricated. Most agitators (dipper rods) are built onto the connecting rod as it is the one part of the engine that moves around the most. As the con rod rotates the agitator dips into the oil and throws it around. Splash doesn’t work well with vertical overhead valve engines as it is difficult to get the upper end of the engine lubricated with any degree of reliability. Most of the side valve (flathead) one cylinder generator engines will have the splash system and it has worked well in them for generations. Some of the horizontal overhead valve engines such as the ONAN KV and KY series are working well with a splash system due to careful design and having the crankcase ventilation system built into the valve cover area. The pressurized system utilizes some type of gear pump to force oil into all critical bearing surfaces of an engine. Just about all of the vertical overhead valve engines are using pressurized systems. The pump usually has a screen on its intake side to stop large particles of dirt, metallic shavings and miscellaneous loose engine parts from getting into the pump. The more expensive engines then pass the oil through... Read more

RV Generator Starting systems, Part 15

RV generators have either rope or electric starting systems. The rope is the old standby and is a carry over from lawn mower engines. Most modern rope systems incorporate a spring loaded compression release mechanism in the engine to ease starting of the larger engines and to help keep from breaking your arm if they kick back. The only thing you can do to a rope system is to possibly carry an extra rope and enough tools to change it out. A broken rope can ruin an otherwise good boondocking trip. Please don’t use plastic coated braided wire as a replacement. If the engine kicks back, it will twist/rip the entire front sheet metal housing off the engine. Don’t ask me how I know. Read more  Read More →

RV Generators Operation – Part 14

Operating the little ones and the big ones Operating RV generators is easy if you follow a basic set of rules. Keep the fuel fresh and clean in the case of gasoline and diesel fuel. Stale gasoline will cause hard starting, low power and varnishing in the engine fuel components. Plus, it smells like old paint. Old diesel fuel will support the growth of algae that will mess up the filters as well as fuel pumps and injectors. Read more  Read More →

Voltage regulating systems. Part 13

Electrical generators must have some form of voltage regulation. Without it, the generator will either run as a motor or overload itself and burn up. There are as many systems available as there are regulator designers and the schemes they can think up. That being said, there are a few basic systems that are in use today that would bear scrutiny. Read more  Read More →

RV Generator Control Systems – Part 12

A generator control board must: 1. Receive a start signal from a manual switch or an outside source such as a remote switch or a system management panel. These could be positive or negative voltage signals depending on the engineer that designed it. Read more  Read More →

Automatic transfer switches. Part 11

Automatic Transfer Switches (ATS) for RV’s come in various sizes and configurations. Let’s see what we’re switching and then what we will need to do it. RV’s come in two basic electrical service configurations, 30 amp and 50 amp. The 30 amp is just an overgrown extension cord that carries 30 amps of 120 volts from a heavy duty 3 wire receptacle and plug to the camper electrical system. It has one hot wire, one neutral wire and one ground wire. A 50 amp system is a little different. It has a heavy duty 4 wire receptacle and plug and features two ‘legs’ of 120 volts (totaling 240 volts) with each leg capable of 50 amps. The neutral and ground wires are also in this setup. It is an undersized version of the 200 or 400 amp system that feeds your house or small business. Read more  Read More →

Next Page »