Device for initiating the remote feed of electrical users

Claim 3

A circuit arrangement for checking a resistance of a remote feed loop and thereafter safely providing a feed current to the remote feed loop after checking for an interruption, comprising: a remote feed loop having a plurality of electrical users series-connected in a loop which is free of devices for automatically closing the feed loop in front of an interruption location; diodes polarized in a blocking direction for the remote feed current and connected parallel to the users; a loop resistance of the closed loop without interruptions being less than human body resistance; a feed device at a feed location containing a dc source; and said feed location including means for checking a resistance of the remote feed loop by providing a test voltage relatively safe to the human body which induces a test current which flows oppositely relative to the remote feed loop feed current, and which further includes means for switching on the remote feed current if a value of the resistance identified at the feed location as determined from the test current of the remote feed loop lies below a prescribed test value chosen such that an interruption can be identified even if a human body shunts the loop at the interruption.

Claim 4

A circuit arrangement for checking a resistance of a remote feed loop and thereafter safely providing a feed current to the remote feed loop after checking for an interruption, comprising: a remote feed loop having a plurality of electrical users series-connected in a loop which is free of devices for automatically closing the feed loop in front of an interruption location; diodes polarized in a blocking direction for the remote feed current and connected parallel to the users; a loop resistance of the closed loop without interruptions being less than human body resistance; a feed device at a feed location containing a dc source; and said feed location including means for checking a resistance of the remote feed loop by providing a test voltage relatively safe to the human body which induces a test current which flows oppositely relative to the remote feed loop feed current, and which further includes means for switching on the remote feed current if a value of the resistance identified at the feed location as determined from the test current of the remote feed loop lies below a prescribed test value chosen such that an interruption can be identified even if a human body shunts the loop at the interruption.

Claim 5

A circuit arrangement according to claim 2 wherein the feed location has a changeover means for polarity-reversed connection of the remote feed loop to the feed location, said changeover means being controllable by said means for checking the loop resistance.

Claim 6

A circuit arrangement according to claim 3 wherein the feed device has means for switching from a constant current source to a constant voltage source.

Claim 7

A circuit arrangement according to claim 4 wherein the remote feed loop is provided with shunt arm means which are conductive only for currents having the direction of the test current.

Claim 8

A circuit arrangement according to claim 5 wherein the shunt arm means are comprised of a series connection of an ohmic resistor and a diode polarized in a blocking direction for the remote feed current.

Claim 9

A circuit arrangement according to claim 5 wherein the shunt arm means are connected to assist fault locating means.

Claim 10

A circuit arrangement according to claim 7 wherein a common power source is provided for checking the loop resistance and for fault location.

Claim 11

A circuit arrangement according to claim 2 wherein the feed location has a relay and means are provided for controlling current flowing in the remote feed circuit, and changeover contacts of the relay connect the remote feed loop in a current-free condition to the dc source with interchanged remote feed current paths.

Claim 12

A circuit arrangement according to claim 9 wherein a display means is provided at the feed location for measuring current flowing in the remote feed circuit, and a sensitivity range of the display means being switchable with assistance of the relay.

Claim 13

A circuit arrangement according to claim 5 wherein the shunt arm means are dimensioned such that the resistance of the loop as determined from the test current is always higher than said prescribed test value given an interrupted remote feed loop shunted at any interrupt location by a human body resistance.

Claim 14

A circuit arrangement for checking a resistance of a remote feed loop and thereafter safely providing a feed current to the remote feed loop after checking for interruption, comprising: a remote feed loop formed of a series connection of a plurality of electrical users connected in a closed loop which is free of devices for automatically closing the feed loop relative to an interrupt location; diodes polarized in a blocking direction for the remote feed current and connected parallel to the users; shunt arm means being provided at a plurality of locations between opposite sides of the loop, each of said shunt arm means comprising a series connection of an ohmic resistance and a diode polarized to substantially completely block when feed current is applied to the loop; a feed device at a feed location containing a dc source; and a loop resistance of the closed loop without interruption with the shunt arm means and at the feed device being less than human body resistance; said feed location including means for checking a resistance of the remote feed loop by providing a test voltage which is relatively safe to human contact which induces a test current which flows oppositely relative to the remote feed loop feed current, and which further includes means for switching on the remote feed current if the resistance of the remote feed loop lies below a prescribed test value chosen such that an interruption can be identified even if a human body shunts the loop at the interruption.

Claim 15

A circuit arrangement for checking a resistance of a remote feed loop and thereafter safely providing a feed current to the remote feed loop after checking for interruption, comprising: a remote feed loop formed of a series connection of a plurality of electrical users connected in a closed loop which is free of devices for automatically closing the feed loop relative to an interrupt location; diodes polarized in a blocking direction for the remote feed current and connected parallel to the users; shunt arm means being provided at a plurality of locations between opposite sides of the loop, each of said shunt arm means comprising a series connection of an ohmic resistance and a diode polarized to substantially completely block when feed current is applied to the loop; a feed device at a feed location containing a dc source; and a loop resistance of the closed loop without interruption with the shunt arm means and at the feed device being less than human body resistance; said feed location including means for checking a resistance of the remote feed loop by providing a test voltage which is relatively safe to human contact which induces a test current which flows oppositely relative to the remote feed loop feed current, and which further includes means for switching on the remote feed current if the resistance of the remote feed loop lies below a prescribed test value chosen such that an interruption can be identified even if a human body shunts the loop at the interruption.