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RE: AccuVote-TS power-related questions
what it's worth, all the units I observed in Alameda were daisy-chained and
had no problems. ...Pat
Ian S. Piper
Diebold Election Systems,
Numerous AccuVote-TS units
configured in daisychain formation in the DeKalb County (amongst others) in
the Georgia elections received insufficient AC power, despite being
connected to AC power. Units not daisychained apparently
did not experience these problems.
Piper] I don't think you have enough information to support your
conclusion. Although details are rather scarce immediately after
an election, it would be useful to get more info on the situation to
determine what really happened. Info such as,
- Where were the voting centers where
this problem occurred.
- What are the serial numbers of
the units that experienced the problem.
- Was the power connection from the booth to the unit
secure in each case?
- Were those cables were tested to ensure that they were
connected inside the
BTW: What is meant by "insufficient
- What effect would power cable length,
configuration, shielding, or any other cabling characteristics have on the integrity of power
delivery in the context
[Ian S. Piper] Our power supply is a
wide ranging type that can operate on an AC voltage as low as 80Vac.
The cable lengths used in elections wouldn't be an issue, unless they went
to ridiculous extremes. Personally, I'd limit extension cord
lengths to a total of 100 feet per daisy chain and I'd use a heavy wire
gauge extension cord.
- How much power is lost from the power
transferring through the AccuVote-TS unit itself?
[Ian S. Piper] There is no power lost; it is
consumed. Power is determined by voltage and current.
The voltage is constant between machines. Each unit would
consume anywhere from 0.4 Amps (Idle with a fully charged battery) up to
1.5 Amps (Fast charging a flat battery).
- What is the ceiling number of units that may be
daisychained from one power outlet?
Piper] The limit on current is 10 Amps as would be dictated by the
circuit breaker on the first booth of the daisy chain. As we don't
know how many units in a daisy chain have charged or
discharged batteries, we have to assume the worst, which is
that each unit is drawing the most current possible (1.5 Amps while
fast charging a flat battery). With a 10 Amp circuit breaker on the
first booth, it can supply 1.5 Amps to up to 6 units in a chain. If
the units aren't fast charging you could do more, but in a situation
where the AC power is out in the whole building and the
batteries are used to a flat condition, when the AC power comes back up,
you'd have all the units fast charging and drawing up to 1.5 Amps
each. Therefore, you'd want to stick to the 6 unit limit on a daisy
NOTE: When the units are turned off and charging a battery,
the worst case is a 1 Amp current draw, so therefore 10 units can be daisy
chained in a warehouse charging setting.
- What power cabling may be used, other than our
own designated ones?
Piper] The customer can use extension cords and power bars to deliver
power to the units as long as they are rated to carry at least 10
Amps. Our power cables are rated for 10 Amps.
- Is it the case that in order to
not overload the power drawn from a single power jack, the jack should be
connected exclusively to a power circuit, ie. the circuit should service
no more than that power jack. Would there be any simple tool (other
than a voltmeter) available that could determine that a power jack is
connected exclusively to a power circuit?
Piper] You don't need to have a dedicated circuit for the outlet that
the daisy chain is attached to. Even if there are more outlets on
that circuit, the answer is "don't use them."
There's no simple tool to determine that an
outlet is isolated from others. An electrician can make that
determination using some tools that put a frequency on the circuit and
sensing which devices (lighting or other outlets) share that
circuit. Other than that, the old "turn the breaker off and see what
is not working" approach is simple enough to determine what is on the
circuit. Power capacities should be part of the
survey at each vote