Getting Started 1-9
Power and Electrical Considerations
Choosing a Power Supply
The XP 3000 is powered by a 24VDC line via the DB-15 connector. The 24VDC supply
for a single XP 3000 should meet the following basic requirements:
• Output voltage: 24V nominal
• Output voltage tolerance: ±10% minimum, ±5% preferred
• Output voltage regulation: ±1% with varying line (input voltage) and load
• Output current (not including loads other than a single pump):
– ≥ 1.5A for power supplies with minimal capacitance
– ≥ 850mA for power supplies with internal filter capacitance of at least 1000
µF per amp of output current
– ≥ 850mA for power supplies with external capacitance of at least 1000 µF per
amp of output current (aluminum electrolytic capacitor preferred)
• Output voltage ripple: 50mV rms maximum at full load
• Conformance to required safety and EMI/RFI specifications
• Voltage turn-on and turn-off overshoot: < 2 volts
• Minimum current load (for switchers): see “Switching Power Supplies” in this
chapter.
To meet the above basic requirements, the supply must incorporate either linear or
switching regulation; it must have adequate output filter capacitance.
A current-limiting power supply is recommended. Current limiting above 1.0A is
acceptable, assuming that no additional equipment is operated from the supply.
If the power supply uses current feedback, the time-current foldback point must be
sufficient to allow charging of a 470 µF capacitor without folding back. If an external
capacitor is used, exercise care to ensure that the supply always starts after foldback,
particularly at low AC line voltage.
Integrating a Power Supply
When a power supply is used to operate more than one XP 3000 or other device, it must
provide the total average current for all devices. The power supply and filter capacitance
together must satisfy the total peak input current for all devices.
For example, if a system incorporates six XP 3000s with other equipment that together
require 4 amps, a 10A power supply is satisfactory, provided the output filter capacitance
in the supply is at least 10,000 µF:
6 x 0.85 = 5.1A; +4A = 9.1A (choose a 10A power supply)
If the power supply filter capacitance is less than 10,000 µF, use either additional
external capacitance or a 15A power supply:
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