Anyone running a shoreline isolation transformer for AC powered gear in a vehicle (ENG, EMCOMM, Medical imaging, etc)?? If you are, what brand is it?
Martin
Isolation Transformers in Vehicles??
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spareparts
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thebigphish
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spareparts
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A business associate has a portable multitrack recording setup in a ambulance chassis and is running into venues that will not allow use of the on-board genset.thebigphish wrote:Isolation transformer...hmmm no, what are you running that requires that?
He just did a job where there was measurable voltage between the truck chassis and water puddles on the concrete where it was sitting.(this while he was using the shore line connection).
Well, I guess the first observation might be that he could perhaps use a battery bank and an inverter, depending upon the duration of the events. He might even be able to bypass the AC inputs on his gear and run it directly from the batteries, and thus eliminate a source of 60 Hz hum.
That said - an isolation transformer in and of itself isn't a full solution to the problem. He still should have a safety ground from the vehicle to the earth - either a jumper to a real ground point, or a set of wires on the ground. Otherwise, any leakage current will still be seeking a path, and it might just find that path through a microphone and performer.
That said - an isolation transformer in and of itself isn't a full solution to the problem. He still should have a safety ground from the vehicle to the earth - either a jumper to a real ground point, or a set of wires on the ground. Otherwise, any leakage current will still be seeking a path, and it might just find that path through a microphone and performer.
This is my opinion, not Aeroflex's.
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I WILL NOT give you proprietary information. I make too much money to jeopardize my job.
I AM NOT the Service department: You want official info, manuals, service info, parts, calibration, etc., contact Aeroflex directly, please.
Sounds like there is an issue with the common ground
that should be carried with the shore-line power cable
and connectors. Another issue may be the source of
the power that was being used has lost it's earth ground connection.
Sounds like time for an electrician to go look at the
power feed your using. Also make sure that the vehicle
frame is connected to the electrical feed your using from
the shore power.
It wouldn't hurt to take a measuement each time you
set this vehicle up at a field location. Measure between
the metal body of the vehicle and some form of an earth
ground stake. It won't take more thatn a short push in
rod of about 6 to 8 inches for a decent voltage reading.
If you find any voltage, best go find out why the electrical
feed your being given has such a poor ground supplied.
Use of an isolation transformer is one way to establish
your own ground. Just remember that you will need to
drive a ground rod in this application. The NEC requires
that you re-establish an earth ground for protection.
The ground rod will be connected to what you establish
as the low side or neutral / ground of the electrical
distribution system you have now created.
Jim
that should be carried with the shore-line power cable
and connectors. Another issue may be the source of
the power that was being used has lost it's earth ground connection.
Sounds like time for an electrician to go look at the
power feed your using. Also make sure that the vehicle
frame is connected to the electrical feed your using from
the shore power.
It wouldn't hurt to take a measuement each time you
set this vehicle up at a field location. Measure between
the metal body of the vehicle and some form of an earth
ground stake. It won't take more thatn a short push in
rod of about 6 to 8 inches for a decent voltage reading.
If you find any voltage, best go find out why the electrical
feed your being given has such a poor ground supplied.
Use of an isolation transformer is one way to establish
your own ground. Just remember that you will need to
drive a ground rod in this application. The NEC requires
that you re-establish an earth ground for protection.
The ground rod will be connected to what you establish
as the low side or neutral / ground of the electrical
distribution system you have now created.
Jim
spareparts wrote:A business associate has a portable multitrack recording setup in a ambulance chassis and is running into venues that will not allow use of the on-board genset.thebigphish wrote:Isolation transformer...hmmm no, what are you running that requires that?
He just did a job where there was measurable voltage between the truck chassis and water puddles on the concrete where it was sitting.(this while he was using the shore line connection).
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spareparts
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The shore cord is 2/4, through 100A pin & sleve connectors. He provides a pigtail adapter to the venue's electrician. If they don't have one, his plan going forward is to hire a licensed electrician to make the connection for him.
The truck has provision for a ground rod already, was added along with multiple flexible jumpers between the box & chassis.
BTW, He routinely checks for fault current between his gear and house systems. Aside from the safety concern, it reduces noise in the recording.
The truck has provision for a ground rod already, was added along with multiple flexible jumpers between the box & chassis.
BTW, He routinely checks for fault current between his gear and house systems. Aside from the safety concern, it reduces noise in the recording.
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spareparts
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Stopped by the place where the recording truck is supposed to work over the weekend. The "Electrician" they hired to hook up the pin & sleeve receptacle used SER (AKA Wonder cable) to feed it. THere is NO Ground connected. The wrap shield is tied to the neutral pin.
That's scary enough, add aluminum wire to a CU only connector, and a NEMA 1 enclosure. Already called the local building inspector to either get it fixed or removed.
That's scary enough, add aluminum wire to a CU only connector, and a NEMA 1 enclosure. Already called the local building inspector to either get it fixed or removed.