Alternators
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The Delcotron DN-Series is the name given to a range of two 12V negative-earth dioderectified alternators produced by the AC-Delco Envision of General Motors Ltd. Both are threephase, full-wave generators which incorporate microelectronic integrated-circuit voltage regulators. No output current control is required as the machines are inherently current limiting.
Model 0/28, which has a nominal rated output of 28amp at 6500 rpm, is designed for passenger cars and vans, while Model 5/35, with a nominal rated output of 37amp at 6500 rpm, is also suitable for light trucks. Maximum operating speed for sustained running is 12,000 rpm although transient speeds up to 16,000 rpm (which may, for example, be produced during gear changing) are readily accommodated, The 14-pole rotors are dynamically balanced for smooth running and welded joints are used between the rotor coil and slip-ring leads. The drive shaft runs in a 17mm ball bearing at the drive end and a 1 Omm needle roller bearing at the slip-ring end.
Rectification is by means of a six-diode power bridge network which is accommodated within the slip-ring end frame and the indicator charge lamp is operated by three diodes which are resin-bonded in a plastics holder.
The integrated-circuit regulator consists of solid state devices and micro-electronic circuits hermetically sealed inside a plastics moulding. Special features include temperature compensation of the output voltage and an over-voltage protection circuit. The regulator is housed within the slip-ring end frame and requires no maintenance adjustments; there are no parts, external wiring is eliminated and the electronic sensors are unaffected by moisture, ageing or vibration. Made by: AC-Delco Division of General Motors Ltd, Dunstable, Bedfordshire.