The power generators, depending on its complexity, can have several auxiliary devices necessary for its operation and which are chosen according to the type of engine, alternator, canopy/container, to where it will be installed or to the conditions of use. We will be able to see many examples together in another article. Anyhow, most generators have at least one of these devices:
-engine water preheater,
It is important to verify that they are functioning and that they are doing their duty keeping the engine warm (for the first two) or that are preventing moisture on the windings (for the last)
For some it is sufficient to check the temperature with a heat gun directly on the motors head or near the oil pan to establish that the preheater works but many modern engines have a real control over the minimum temperature from the head in order to enable the start-up, therefore it is good to measure the actual temperature reached by the preheating in several points of the water circuit. In this way you can modify it by adjusting the thermostat if it is too low or too high (a constant high preheating temperature causes unnecessary wear on the gaskets, hoses … )
A more specific electrical check can be performed after the preheating has been suitably disconnected electrically.
A more specific electrical check can be performed after the preheating has been suitably disconnected and after disconnecting the power supply wires with an ordinary multimeter. You can check for signs of dispersion to the ground and understand if the resistance is deteriorating or still in good condition.
Depending on the year of construction, it can be composed and equipped with old or new generation tools: it can be electromechanical, with many relays or electronic with cards of various kinds.
In each and every case everything happens through electrical contacts, wires, signal exchanges, therefore you will find clamps, connectors, wiring and other electrical equipment to be tested with patience.
The movement itself of relays and contactors, causes with time a loosening of the connections, which can be re-tightened. You should make sure that the clamp is tight, but at the same time gently, you should take care to not overdo it with the risk of damaging the component.
It is advisable to remove the ducts’ covers that house all the bundles of cables so as to see that there were no short-circuits between damaged wires or cablings. This is a sore point, especially in old installations since ducts, wires, copper bars and tunnels are the favourite territory of small rodents that, in addition to finding a very comfortable and sheltered habitat, are very greedy and love the wires and their isolation.
Once I was involved in the maintenance of electrical panels that were seriously damaged by small rodents, which unfortunately are only discovered after they have created the damage, or worse, leaving a whole activity in the dark because when moving between the copper bars of a switching, they caused a short circuit between the phases; or simply because the signal cables between the control units have been gnawed.
Thus, provide a pair of suitable gloves and check well between the cables bundles and if you happen to find traces of rodents, you will have to repair or replace the damaged wire promptly, and notify your client so that he can organize the local disinfection.
With compressed air canisters like the ones used for computer keyboards, it is advisable to blow away all the dust, dirt, cobwebs and all that could deposit on the components inside the panel. Avoid using a compressor that could spray water t in the form of condensation on the electrical contacts.
The rest of the inspections at the control panel are directly related to the functional tests.
Please do not forgot to work by safe way, and remember that the Atuomatic Transfer switch can have parts under power even when the generator are not able to run.