From: Jim Meissner (jpmeissner_at_mindspring.com)
Date: 2002-01-14 19:06:55
Dear Joerg:
>can call an old customer and find out the manufacturer and part
>number of a transformer we used in a high meg ohm wheatstone bridge
>circuit. It would work well for this application.
If this transformer is more or less comparable to the above mentioned
specifications I really would like to hear the price.
> Also there are
> filament transformers
> Does that mean, there is no ferrite core ?
The two above mentioned transformers are 50/60 Hz, no ferrite core. Both use a steel wound torroid, with a large air space between windings.
The wheatstone bridge transformer was about $50 at that time. Also not cheap, but very good.
++++++++++++++++++++++
It is fully IEC601-1 appproved:
"...
I/O test voltage: 6000 Vpk
Safety standards and approvals: IEC/EN 60950, IEC/EN 60601-1
rated for 250 VAC (BSI test report)
..."
Sounds good! How much? Problem solved?
Juergen P. (Jim) Meissner
Check out my Website at www.MeissnerResearch.com
Read about the benefits of the Brain State Synchronizer sounds for improving your life and health.
----- Original Message -----
From: Joerg Hansmann
To: buildcheapeeg_at_yahoogroups.com
Sent: Monday, January 14, 2002 1:50 PM
Subject: Re: [buildcheapeeg]Patient Safety and Isolation Transformer
Dear Jim:
----- Original Message -----
From: Jim Meissner <jpmeissner_at_mindspring.com>
To: <buildcheapeeg_at_yahoogroups.com>
Sent: Sunday, January 13, 2002 8:55 PM
Subject: Re: [buildcheapeeg]Patient Safety and Isolation Transformer
...
>You stated that your preference would be "not" to use batteries.
>
>I suggested that we give the customers a choice of using batteries or
>a transformer.
>
>I offered to help you find a "safe" transformer. A medical grade
>transformer is quite expensive.
A medical grade wall wart power supply (e.g. 230 Vac / 8 Vac 200mA)
could be an alternative to batteries or DCDC converters.
But you said, that it is quite expensive...
>My company manufactured transformers for a few years and I know how
>they can fail unless a lot of special care is taken. There are
>"safe" transformers commercially available. If you want me to, I
>can call an old customer and find out the manufacturer and part
>number of a transformer we used in a high meg ohm wheatstone bridge
>circuit. It would work well for this application.
If this transformer is more or less comparable to the above mentioned
specifications I really would like to hear the price.
> Also there are
> filament transformers
Does that mean, there is no ferrite core ?
...
>> I have just emailed traco power products, the manufacturer
>> of the tmv-en DCDC converter series, if their TMV-EN DCDCs are
>> IEC601-1 compliant.
Today I got answer from "traco power products". They have an even better
product than the "TMV-EN" series, called "THI" series:
http://www.tracopower.com/products/thi.pdf
It is fully IEC601-1 appproved:
"...
I/O test voltage: 6000 Vpk
Safety standards and approvals: IEC/EN 60950, IEC/EN 60601-1
rated for 250 VAC (BSI test report)
..."
Regards,
Joerg
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This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:36 BST