(1) Accessories. Foldout 1 shows the accessories used with the 500-
ampere test stand. During operational conditions part of these accessories are
usually fastened to the test stand. The rest are stored in the provided storage
compartments. The accessories that remain more or less permanent are the mounting
brackets and pivot arm. Each of these accessories is identified in foldout 2.
(a) The permanently mounted accessories are shown in figure 5. Also
shown are the access ports to the driving heads. One is for low speed and the
other is for high speed. The low speed head operates between 800 to 4,800 RPM,
while the high speed head is from 1,830 to 11,000 RPM.
(b) The pivot arm (6) allows the selection of either driving head.
It is held in place by three hexagon studs (7). If the rated RPM of the UUT is
below 3,300, mount it on the low speed head. If the RPM is above 3,300, mount it
on the high speed head. For most cases of generator or alternator unit under test
(UUT), the low speed head will generally suffice for testing.
(c) The pivot arm (6) is pulled outward along the pivot shaft (5)
far enough to clear the hexagon studs (7). The pivot arm can now be swung into
position with either of the driving heads.
(d) When the three stud holes in the pivot arm are alined with the
three hexagon studs, the pivot arm is pushed inward allowing the studs to protrude
through the holes in the pivot arm. The pivot arm is then secured to the test
stand with three hexagon nuts when the mounting flange adapter is put in place.
Nine other hexagon nuts secure the mounting flange adapter to the pivot arm.
(2) Direct driven. Figure 6 shows the direct driven mounting of a
generator or alternator. The driving head shaft is connected to the generator by a
coupling shaft. These two shafts are keyed together with a square piece of metal
called a machine key. There are setscrews that secure the machine key and the
coupling shaft to the driving head.
(a) The shaft coupling (2) is made to fit a generator or alternator
with a large splined shaft. If the generator shaft is smaller, then a spline
adapter (3) is used. This spline adapter mounts between the coupling shaft and
generator.
(b) The direct driven generator (9) is mounted over the middle row
of studs on the mounting flange adapter (8) by sliding the splined shaft of the
generator into the spline adapter (3). The generator can be secured to the
mounting flange adapter (8) with six hexagon nuts.
(3) Pulley driven. Figure 7 shows the pulley driven mounting of a
generator. Here a pulley is connected to the driving head, so the proper size of
pulley must be selected to match the generator pulley (foldout 1).
(a) Mounting. Once the pulley (29 or 30) has been selected, it must
be mounted upon the pulley output shaft assembly (33). The pulley is held by a
brass washer (24) and a retaining ring (23). Before the pulley can be mounted upon
the shaft, the machine key (26) is inserted and then the pulley is installed. The
key locks the pulley to the shaft.
1. The machine key (25) is inserted into the driving head end
of the pulley shaft. The pulley shaft is then slid on the driving head by alining
the keyways. The pulley shaft will slide over the middle row of studs on the
mounting flange adapter. It is secured to the mounting flange adapter with six
hexagon nuts.
OS 010, 4-P7
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