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Unipole Conductor Systems Troubleshooting
We have been informed of, seen and inspected a number of VAHLE systems that have been improperly configured and/or installed (not per VAHLE Specifications). We feel it is a tribute to the quality of VAHLE components and design that these systems continue to operate reliably despite the incorrect installation. However, longevity may be reduced. There are systems that will not operate or function properly if the installation or configuration is not correct. It is our experience that operational issues can easily be fixed by reviewing the system configuration and/or adjusting the installation.
EXPANSION AND CONTRACTION DUE TO TEMPERATURE CHANGE
It is critical to use expansion sections as shown in our catalogs for certain configurations (consult product catalog). Expansion sections will only work properly if fixpoint and sliding hangers are installed at their proper positions. Moreover, sliding hangers must not be installed cocked or against a joint or feed that will restrict the expansion/contraction of the conductor system. Symptoms of this issue include: warping or bending of the conductor rail, joints pulling apart.
COLLECTOR (CONTACT) BRUSH WEAR
The contact brush is the “wear item” on the system. The contact brush is composed of copper graphite. As the brush wears graphite dust may deposit in the conductors. The dust should be periodically removed as it is conductive. If you choose to vacuum the dust you will need to use a vacuum that is designed so that the intake does not flow (designed for cooling) through the motor. We also offer cleaning components (see optional components). If you have excess carbon graphite dust build up or premature brush wear you need to check the installation of the system. Cleaning of dust is typically an annual project (assuming the system in installed in a clean environment).
JOINT AND JOINT COVERS
The proper installation of joints and joint covers is critical to a properly operating system. After installing a joint (and before powering up the system) run your finger or collector over the connection. The connection should be snug, secure and smooth. If there is an edge you should sand it lightly. An edge will act as a file on a contact brush causing it to wear quickly and cause a build up of carbon graphite dust; in extreme cases an edge can cause a collector brush to jump or break. Joint covers must be in place for safety reasons. To identify problem joints on an existing system you can run a collector through the system. The collector should not snag, or when passing over a joint jump (do not have power on the system when doing this).
For the U 10/25 C insulated conductor system (typically on EMS, AEM sysems) it is important to use the VAHLE installation tool. If the tool is not used it is possible for the conductor profile to become deformed (squeezed at the opening). If this occurs the current collect may jam, break or jump. It is also possible that the collector hits the joint covers and moves them out of position. To correct this issue use the installation tool to spread open and reform the conductor (see attached graphic).
LOSS OF ELECTRICAL CONTACT
Some of the most common installation issues include: conductor alignment not consistent, gaps at transfer areas are too wide or conductors are out of alignment, the collector assemblies are installed at the wrong working height, the wrong collector is being used for the system configuration. Symptoms of the above issues include: uneven or premature brush wear, jamming or breaking of collector brushes or arms, loss of electrical contact.
You can get a feel for the quality of the installation by calculating the kilometers of travel for your collectors between brush changes. For an application in a clean environment at moderate speeds brushes should last about 10,000 12,000 + km (6,000 - 7,200 miles).
Complex systems that have many joints, isolations and transfers must be carefully installed to maximize the life of the contact brushes. Conductor rail sections that are cut and installed on site must be de-burred and filed smooth. Likewise alignment and/or gaps at transfer sections must be within VAHLE tolerances. A single rough joint or transfer area will act as a file on contact brush causing premature brush wear. Many rough joints or transfer areas will greatly reduce brush life. Evidence of this problem may be carbon graphite dust deposits.
COLLECTOR HEADS OR NECKS BREAKING
Another sign of installation issues is collector heads or necks breaking. In this event watch a collector assembly run through the system at slow speeds. If the collector binds or jumps, check that area for alignment, damage or installation problems. It is also important to make sure the collector working height is consistent throughout the system (especially at curves). An over-compressed collector could prematurely wear, get jammed at transfers, jump or break.
If you have any operational concerns regarding VAHLE components or systems please give us the opportunity to work with you to identify and correct these. From experience we know that most problems can be resolved and often it can be very easy and quick fix.
VAHLE Certified Installation
VAHLE certified installation technicians are available for complete installation or supervisory services. We highly recommend you use a VAHLE technician for complex installations. VAHLE trained technicians can typically install a system in a third of the time of non-trained installers. Additionally the VAHLE technician's attention to detail at the critical areas (transfers, curves, lift stations, switches, turntables) insures a very smooth operating system, which in turn promotes long life of contact brushes (2 to 4 times the standard life). Our technicians are also available to troubleshoot existing installations.
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