Applications
For checking purity of hydrogen in H2 cooled generators and synchronous converters. The model 380WP will also monitor the safe purging of H2 during shutdown.

Description
The Model 380WP can measure the following gases by switch selection:
Range 1: 0-100% hydrogen in air
Range 2: 0-100% hydrogen in CO2
Range 3: 0-100% air in CO2

The analyzer contains a temperature compensated thermalconductivity (TC) cell, amplifier board, digital readout, range switch, gas flow regulating valve, pump and flow indicator. A recorder output is optional.
The TC cell does not burn the sample nor is it consumed in any way, so it has a life expectancy of over 10 years. Measurement results are fast and accurate. A rechargeable ‘gel cell’ battery provides enough power for about 8 hours of continuous operation and the analyzer can be used while it is being recharged.

Description
Most power generating plants use hydrogen gas to cool the electrical windings within the power generator. This improves operating efficiencies by lowering the losses due to the resistance of the windings. This is commonly known as windage losses.
In order to control these losses and keep efficiencies high, the hydrogen purity must be maintained. Even a slight contamination of the hydrogen by oil vapor, water or air will increase the windage losses in the generator.
As an example, a 1% reduction in hydrogen purity creates a 12% increase in windage loss. A decrease in purity from 99% to 92% can reduce generator output by as much as 2100 KW.

Obviously, this reduction in generator efficiency results in higher fuel costs and replacement power requirements. For example, assuming a replacement power cost of 5 cents per KW/HR, each additional 100 KW of windage loss (assuming 80% capacity factor) costs a utility plant more than $350,000.00 per year.
The other factor to consider of course is safety. Hydrogen/Air mixtures of less than 74% are explosive, so the Nova 436 helps ensure that the purity level never drops to this point by providing alarm contact closures at two levels.
The Nova Model 436 Tri-Gas Analyzer is designed specifically for monitoring hydrogen purity in a power generator or synchronous converter and to monitor the purging procedure during shut down.
The analyzer can measure the following gases by switch selection:
Range 1: 0-100% Hydrogen in Air
Range 2: 0-100% Hydrogen in CO2
Range 3: 0-100% Air in CO2
The Model 436PMN7 analyzer is divided into 2 sections. The Control Section contains the amplifiers as well as the digital readout meter, alarms, range switches and power supply.
The Gas Detector Section contains the thermalconductivity cell, a five way selector valve, gas pressure regulator and temperature control.
A length of cable connects the two cabinets.
A 4-20ma output and two alarms are provided for the range of 85-100% hydrogen in air.
The 436 can be provided in several configurations. The 436PMN7 is the most popular. It has an explosionproof gas detector cabinet and a general purpose rated, panel mounted control cabinet.
The 436N7 has both an explosionproof gas detector cabinet and explosionproof control cabinet.
The 436N4 Gas detector and controls are all housed in one, non explosionproof NEMA 4 wall mounted cabinet. All explosionproof enclosures are UL/CSA/FM approved for CL 1 Div I, Groups B, C, D areas.