BASIC MINIMUM SPECIFICATIONS FOR SCHOOL BUS CHASSIS FOR MOUNTING TYPE A, C, AND D SCHOOL BUS BODIES
The design of school bus bodies is to provide for the safety of pupils and for long range, maintenance free factors as required by Transportation Code 547.7015 and Education Code 34.002.
This is a performance specification. Installer shall consider the following for alternators:
Minimum rated capacity of 140 amps for Type A and 175 amps for Type C & D, fourteen volt (for a 12 Volt System)
Ventilated and voltage controlled
Current controlled, if necessary
Buses Equipped with Air Conditioning and/or Wheelchair Lifts: Type A buses shall be equipped with the maximum rated capacity available from the chassis OEM with a minimum 200 amp alternator or dual alternators. Type C & D buses shall be equipped with an alternator(s) with high output at low RPM with a minimum rated capacity of 270 amps.
Alternator Performance Requirements
It is the responsibility of the installer of the wheelchair lift and/or air conditioner to provide an alternator to adequately maintain the electrical system while the bus remains at OEM idle speeds as well as standard operating speeds. The following conditions shall be considered, but not be limited, to the alternator selection and installation.
Electrical System, Maximum Amperage Draw Test
The installer shall determine the total amperage draw at OEM idle speeds with all electrical items turned on. To determine the greatest draw on the electrical system, the wheelchair lift shall be in operation lifting a minimum weight of 800 pounds during the "maximum amperage draw test."
The cabling shall be inspected to determine sufficient current flow from the alternator to the battery as well as to the ground to maintain proper system amperage requirements.
The alternator selected shall be capable of delivering the required amperage at OEM idle speeds while not sustaining damage or causing damage to the electrical system or components at operating speeds of up to 60 MPH.
Cabling of the alternator and battery system must meet or exceed the requirements of a 320 amp. alternator. All 14 to 29 passenger design capacity school buses are exempt.