The
vibrating type of rectifier utilizes two electromagnets energized by the
alternate current waves to operate a pair of contacts so that, with the wave in
one direction, one set of contacts will close, and with the wave in the opposite
direction, the other set will close. The contacts are placed in connection
with the direct current line through a rocking bar which is also an
electromagnet.
The connections for one form of vibrating rectifier are shown in
the figure at the left. The alternating current supply passes through the
primary winding of a transformer which reduces the voltage. The center of
the secondary coil of the transformer is connected directly with one of the
direct current leads. Opposite ends of the secondary winding are connected
with the two stationary contacts, one end with each contact. With one set
of contacts closed, the direct current circuit is completed through this contact
to one side of the direct current line, while the other side of the direct
current line is completed through the permanent connection to the center of the
secondary coil. With the opposite wave of the alternating current, the
first pair of contacts opens and the other pair closes so that this wave is sent
to the direct current line in the same direction as was the first one.
Such a rectifier will operate properly with the battery
connected in either direction because the polarity of the rocking magnet is
determined by the polarity of the battery connections. The best results in
long life of the contact points will be secured if the polarity of the battery
charging line connections is reversed at each charge.
Sparking at the contacts may sometimes take place due to
differences in the alternating current wave form. Such sparking may be
reduced in the type shown by changing the connection on the regulating
resistance coil. This connection is made through a brass band clamp and
moving the clamp one way or the other will affect the amount of
sparking.
Sparking will also result from long use and wear. This may
be cured in great measure by making a new adjustment of the movable contact
points. The contact adjustment is made to the best advantage with the
batteries about half charged, or at 2.3 volts per cell. The contact screws
may then be turned to the position at which sparking is practically absent,
after which all locking devices should be carefully tightened..
The above is copied from Automobile Battery Care
and Repair by Harold P. Manly, 1920.
