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Battery powered equipment found in today’s telecommunications (and other) facilities utilize a disconnecting means.
A disconnect provides a simple means to isolate a string of batteries for maintenance purposes. In addition, some local municipalities or fire department regulations require a remote means for disconnecting the battery string in the event that emergency personnel need to enter a facility. The DC disconnect, with a remote EPO switch option, addresses this requirement.
The National Electrical Code also provides guidelines when a battery disconnect is used. See the Code here.
EEE’s battery disconnects typically are mounted on top of the battery rack in a vertical or horizontal orientation. An alarm contact for monitoring the disconnect position is provide as standard.
Disconnects are designed for “out-of-the-box” direct interface to over 165 industry standard VRLA batteries. VIEW SUPPORTED BATTERIES HERE
Each disconnect is supplied with a battery specific custom mounting kit and copper termination plate. Expected installation time is 30 minutes. VIEW CUSTOM INSTALLATION HERE
Depending on disconnect ampere size and orientation, headroom above the battery is required. VIEW DISCONNECT DIMENSIONS HERE
A current shunt is a very low resistance connection between two points in an electric circuit that forms an alternative path for a portion of the current. The voltage drop across the shunt is proportional to the current through the shunt. All shunts are supplied with a 50mV output. The output voltage follows this formula:
(Actual Current) x 50mV = Measured mV
(Shunt Current Rating)
Example: Shunt rated 1500 amp with a 50mV output carrying 1000 Amps:
(1000 Amps) x 50mV = 33.3 mV
(1500 Amp)
Shunt output voltage is wired to a terminal block and is monitored by others.
To maintain the best accuracy, continuous operating current should not exceed 2/3 of the shunt rating. As the current approaches 100% the accuracy decreases by approximately 2%. To insure proper operation the shunt temperature should not exceed 145 degrees C. (roughly 130%). At 145 degrees permanent damage will occur. We typically upsize the shunt one rating above the current ampere rating of the disconnect.
EEE manufactures both disconnect switches and disconnect breakers. The footprints are identical, the difference is internal. It is important to understand the differences.
End user specifications often define the type of protection required. Some users want catastrophic protection only without the risk of a surge on short term overload to take them offline.
The ability to remotely open the disconnect may be required by the customer, fire department or local municipality. This requires the following:
1. A factory installed trip coil internal to the disconnect.
2. A remotely operated means to energize the coil, supplied by EEE or others.
Trip coils are utilized for Remote Open / Manual Close operation only. These battery disconnects are typically installed on 24 or 48 VDC systems. Most often the trip coil is powered by the same 24 or 48 VDC battery the disconnect is mounted on. This coil is pre-wired from the ungrounded side of battery disconnect through a fuse and wired to a terminal block on the side of the disconnect. (See wiring diagrams below).
The user may desire to use a 120 VAC source to control the remote open function. See the 120 VAC wiring diagram below.
The remote operating means can be any dry contact closure with contact ratings sized per the Electrical Data table below. This generally is a manually operated push button type station supplied by EEE. It could also be a customer supplied push button or controlled by a computer or building monitor system capable of closing a contact (by others) as the user sees fit.
Several options are available for supplying the contact closure:
Many users have multiple batteries installed at a single site. If all the disconnects are supplied with the remote open option, the user will need to determine how the disconnects are to be operated:
1. Each disconnect has its own dedicated EPO switch
2. All disconnects are opened together by a single EPO switch
This application is similar to a single disconnect with an EPO switch. Each disconnect is wired as shown below.
If it is desired that a single EPO push button operate multiple disconnects at the same time, each disconnect must be controlled by its own electrically isolated contact. The EEE supplied stations (Options R, RS and RK), can accommodate up to 8 electrically isolated contacts.
When is it desired that multiple disconnects be operated from a single contact closure (EPO switch or other means) the disconnect trip circuits must not be daisy chained or tied together in parallel. This can lead to damage to the shunt trip coils. The proper connect diagram for multiple disconnects must be followed.
Proper orientation depends on the specific battery type and battery stacking configuration used. The bus connection to the battery will exit the disconnect from either the right side (RAR) or left side (RAL) of the disconnect. If necessary the orientation can be reversed in the field. VIEW REVERSE ORIENTATION INSTRUCTIONS
NOTE: The load cables will enter disconnect in the direction shown (see RED circles), parallel to the top of the rack. For cable entry from overhead, see RARV / RALV Option.
To determine RAR or RAL configuration, verify the following:
1. Determine if the disconnect connects to the (+) or (-) battery terminal.
2. Orient the disconnect 90 degrees in the direction that does not interfere with the opposite battery polarity.
3. Insure disconnect does extend off the end of the battery
Ladder Rack mounting option utilizes a unique “hanger” system to allow easy mounting on ladder or cable racks. The disconnect can be mounted in any orientation. Typical installation is less than 5 minutes. Ladder rack mounted disconnects can be supplied with or without a metering shunt option. Available 100-1800 Amp.
NOTE: Front protective shielding not shown for clarity.
Relay rack mounting option will accommodate both 19” and 23” industry rack systems. The disconnect requires 7” of vertical space in the rack. Rack mounted disconnects can be supplied with or without a metering shunt option. Available 100-1800 Amp.
NOTE: Protective shielding not shown for clarity.
Optional Mounting – NEMA1 Enclosure – Wall Mounted
Wall mounted disconnect enclosures can be supplied with or without a metering shunt option.
NOTE: 1200 Amp Unit shown. Available 100-1800 Amp.
Optional Mounting –– Wall Mounted on Unistrut – No Enclosure
Wall mounted disconnect where no enclosure is used. Unistrut for mounting provided. Wall mount units available with or without the metering shunt option.
Frame sizes from 100 to 2400 amp available.
NOTE: 800 to 1800 amp footprint shown. Front protective shielding not shown for clarity. Lugs supplied by others
