SPECIFICATION OF THE DOWN HOLE MUD ALTERNATOR

Brief Technical Description
The generator comprises a three phase alternator, rectifier and an efficient switch mode power supply which can provide up to seventy Watts of regulated dc power, customer configured for any output voltage to a maximum of 50Vdc. The alternator is short circuit protected and provides ten through conductors for functions defined by the customers’ application. These wires may be terminated with the customers’ choice of connectors.

Alternator rpm is indicated in two ways. A 5V logic level asserts when the alternator is above the regulation point and a serial stream of 5V pulses continuously indicate alternator rpm. Internal firmware also provides an elapsed time log to record the operating hours of each alternator. The alternator is powered by a reaction turbine which extracts energy from the mud flow and converts it to mechanical power.

All parts within the alternator and turbine assembly are designed to be field serviceable with purpose tools and include the bearings, the centralisers, the stator and rotor. The operating life of any wear part is greater than 300 hours.

Alternator Specification @ 150°C

1) Electrical:

• Alternator: Three phase star connected.
• Output Power: 70 Watts @ 150°C.
• Flow Rates: 300 USGPM minimum for controlled voltage.
• 550 USGPM maximum flow rate.
• 580 USGPM absolute maximum flow rate.
• Output Voltage: Customer defined to 50V max.
• Max Output Ripple: 900mV rms (All load conditions)
• Short Circuit Protection: Continuous.
• RPM Indication: 5V Pulse.
• Through Conductors: Up to ten, end to end.
• Interconnections: Customer defined connectors.
• Battery Switching: Automatic via integral diode.
• Condition Monitoring: Elapsed hour counter.

2) Mechanical:

• Tool Length: 73 inches (max).
• Tool Diameter: 1-7/8 inches (nominal).
• Wear Sleeve: SS440C – HRC 55/60.
• Collar O/D; 4-3/4 inches (nominal).
• Bore back (box end) 78/78.3mm diameter by 1.65 metres length.

3) Pressure:

The alternator stator contains a three phase winding and is fully encapsulated to allow the stator to keep its mechanical and electrical integrity up to 20,000 psi. All other electrical and electronic modules are housed within a 25,000 psi, 1-7/8 inches BeCu Pressure Case.

4) Vibration:

Tested with a random spectral density equivalent to 20g rms over a frequency range from 15Hz to 500Hz for one hour’s duration for each axis.

20g Random Vibration:

PSD: 0.4g²/Hz to 15Hz to 30Hz. 0.8g²/Hz 30Hz to 500Hz.

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