US1646943A - Electromagnetic switch - Google Patents

Description

I 1,646,943' Oct. 25,1927. H N WADE ELECTROMAGNETIG SWITCH Filed Aug, '7. 1919 A TTORNEY Patented CL 25, 1927.

. UNITED "STATES fPaieniorric.t

HENRY N. WADE, OF MILWAUKEE, WISCONSN, ASSIGNOR TO THECUTLER-HAIVI1\EER MFG. CO., OF MILWAUKEE, "VVISCONSIIFT,` A CORPORATION OF WISCONSIN.

ELECTROMAGNETIC swimcn.

Appiicauonzfned August 7, 1919. serial No. 315,803.

Another object is to provide a switch which may be readily designed and adjusted to respond at, a given frequency of the current supplied thereto and to be unresponsive i at all higher frequencies.

Other objects and advantages of the invention will hereinafter appear.

The accompanying' drawing illustrates onev embodiment of the invention which will now be described, it being understood that the embodiment illustrated is susceptible of various modifications without departing from the scope of the appended claims.

vIn the drawing,

Figure 1 is a side view of the switch, and

Fig'. 2 is a front view thereof.

The switch illustrated comprises a contact arm l of magnetic material coloperable with a stationary contact 2, said arm being 3 pivotally supported on a magnet frame 3 which carries a winding 4 to effect attraction of said arm and a coil 5 to function as hereinafter set forth. The magnet frame `and stationary contact are fixed to an insulating support 6 and a spring 7 is connected at one end to the contact arm l and at its other end to a member 8 adjustably securedv to the base to normally disengage said. arm from the stationary contact.

The magnet frame has parallel pole pieces 9, l() and 11 the pole pieces 10 and 11 being formed integrally therewith. TheV 1ntermediate pole piece 10 which isrecta-ngular in cross section forms a supporting core for the winding 4 and also servesl to pivotally support the contactarm, said pole piece having its end bifurcated to receive a block 12 fixed to said arm and carrying a -pm' 13 passing through .said block. The pole piece 5U 9 is cylindrical and forms a supporting core for coil 5, the latter preferably compris ing a plurality of copper washers of varying thickness. This pole piece is mounted on a threaded stud 14 projecting through the magnet frame and base and the washers 5 are detachably ,secured thereonby screws 15 'threading into the magnet frame. The pole piece 11 which as best shown in F ig. 2 is V-shaped in cross section, serves as a stop for thelower end of the Contact arm l, said arm carrying an adjustable non-magnetic set screw 16 to engage said pole piece.

It will thus be observed that the magnetic fiuX of the winding 1 has parallel paths through the pole pieces 9 and 11 respectively, whereby it produces actuating and lockout pulls on the contact member, the arrangement being such that the actuating pull preponderates the lockout pull eX- cept as hereinafter set forth. Further it will be observed that if thewinding 4 is supplied with an alternating, pulsating or other undulating current its magnetic flux which threads the coil 5 will induce currents in the latter varying with the frequency of the currentsupplied to said winding 4, whereby coil 5 -will function as a damping coil to oppose the magnetic flux tending to attract the arm 1. Thus the coil 5 will cause a part Vof the flux to traverse the aforesaid parallel path through pole piece 11, the percentage of fluir traversing this path varying with the damping currents induced in coil 5. The

' opposing effect of coil 5 as is well understood will increase with an increase in frequency of the current supplied to winding -1 and will decrease with a decrease in the frequency of such current whereby a maximum percentage of flux will be caused to traverse the pole piece 11 at maximum frequency,V wliilea minimum j )eicent-age of flux will be caused to traverse saidpole piece at minimum frequency. Obviously, therefore, the switch willlte'nd to respond at a certain frequency and to lock out at all higher frequencies. Y j i The switch illustrated may be adjusted in various ways for variationfof its sensitiveness through wide range. For example, the sensitiveness of the switch may be varied by varying the size of coil.5 or by relative variation of the air gaps between the contact arm and the pole pieces 9 and 11 by adjustment of the set screw 16 or by varying the tension of the spring 7 to vary the force opposing attraction of arm 1. With the coil 5 formed as illustrated the size thereof may be readily varied by removal of the desired number of washers, the varying thickness of the washers enabling a number of variations exceeding the number of washers.

I/Vhile the switch illustrated is designed and adjusted to respond only at frequencies below a predetermined limit it is obvious that a switch embodying the same elements and principles might be made to respond only when the frequency of the current supplied thereto exceeds a givenv limit. Also various other modifications of the switch are possible without departing from the scope ot' the appended claims.

What I claim as new and cure by Letters Patent is: y

l. In an electric switch, in combination a movable contact member, electromagnetic means to be supplied with anundulating current to produce a magnetic flux for opdesire to seerating said member and a coil threaded by such magnetic iluX to produce an opposingr magnetic flux rendering said means inoperative tov actuate said member while the frequency of the currentv supplied thereto `exceeds a given limit, said coil comprising a plurality washers of varying thickness.

2. In an electric switch in combination a movable contact vmember an electromagnet having parallelmagnetic circuits whereby the magnetic liux thereof producesiopposng 'pulls on said member and a damping coil scribed n'iy naine.

HENRY N. WADE.

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