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| Growler Information The information and illustration included on this page came from "Audels New Automobile Guide" 1940 edition. A growler is an audible testing device for armatures. The growler will detect grounds, short circuits, open circuits, reversed coils. How does a growler work? The alternating current which is used sets up vibrations at the contact surfaces between armature core and growler poles resulting in a buzzing or growling noise, hence the name "growler". A growler with an armature in place and current turned on is very similar to a transformer; the iron of the growler in contact with the steel body or core of the armature, forming an all metal path or core, for the magnetic circuit. The growler winding is the primary which takes current from the power line, and the winding on the armature is the secondary, in which current is induced by the alternating action of the magnetic field developed in the iron core. If the armature winding is in proper condition, there is no current flow in the armature coils. If, however, the armature is short circuited, or has a short, a heavy current is induced in the short circuited coil, which strongly attracts a hack saw blade. |
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| Growler manufactured by the Allen Electric & Equipment Co. of Kalamazoo, Michigan. In construction there is a U shaped piece of soft iron, called the core, around one section of which is wound many turns of insulated copper wire. The upright legs are called the poles, and the armature to be tested is placed in the open end of the U in contact with the two poles, as shown. Parts are: 1: Long test points with insulated handles. 2: Contact fingers held in bakelite tube. 3: Laminated core. 4 operating switch. 5: End frames. 6: Hack saw blade for testing. 7: Base. 8: Holes to see tell-tale light. 9: Housing to protect rheostat and meter. 10: Panel carrying rheostat and meter. 11: Extension cord. 12: Ammeter with zero adjustment. 13: Adjustable triple wound rheostat. |