Colin &c
On our last trip down the road of powering vocas from wheelchairs, I was
looking at the "Volz" power unit sold through Liberator. I couldn't find
much info on it & the client changed tack completely. I hoped that it would
avoid us building our own psu. Does this help/ does anyone know more?
> ----------
> From: Colin Geggie[SMTP:[log in to unmask]]
> Reply To: A discussion list for Assistive Technology professionals.
> Sent: 28 June 2002 12:38
> To: [log in to unmask]
> Subject: Powering Ventiltors from Powered Wheelchair Batteries
>
> Dear All
>
> I'm writing to ask if any of you have ever been asked to make the
> necessary electrical connections to enable a ventilator to be powered from
> a wheelchair's +24V batteries. Here in Lothian, we have been asked to do
> this work for three patients over the last year. All of these patients
> use Breas Medical ventilators that have a +24V connection to enable the
> connection of an external battery pack. The result of the work is that
> the ventilator can be mounted on the rear of the powered wheelchair, on a
> specially manufactured tray, without the need for an external battery pack
> to be fitted to the wheelchair.
>
> Powering the ventilator from the wheelchair batteries reduces the amount
> of hardware that has to be fitted to the powered wheelchair and it enables
> the external battery pack to be kept as a reserve supply for emergencies.
>
> Recently the department in Lothian that provide the ventilators to
> patients has informed me that they don't know of any other centres that
> are providing these electrical connections and indeed they know that some
> refuse to do it. This surprises me because it seems logical to carry out
> this work. Initially I contacted Braes and I was informed that there
> would be no particular problem in making this connection. My risk
> analysis indicated that we could only proceed with this work if the
> ventilator had an internal battery supply that it would switch to
> automatically in the event of a failure in the wheelchair electrical
> supply. The internal battery pack provides approx. 1 hour of
> ventilation which is more than enough time to connect either the external
> battery or a mains supply.
>
> My questions are, have any of you been asked to do this type of work and
> if so have you agreed or refused and what are the reasons behind your
> decision?
>
> On a related issue, we have also powered communication aids from the
> powered wheelchair batteries. I have concerns about generating mains type
> voltages on wheelchairs. I've therefore avoided using handy mains voltage
> converters and I've included dc/dc regulators to convert from the
> wheelchairs +24V to the required dc voltage. Do any of you have views on
> the use of Handy Mains converters on powered wheelchairs?
>
> Colin Geggie
> Clinical Bioengineer
> Rehabilitation Engineering Services
> Eastern General Hospital
> Seafield Road
> Edinburgh
> EH6 7LN
> Tel. 0131 536 4695
> Fax. 0131 536 4840
>
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