JPS5830228Y2 - Magnetic braking device for integrated wattmeter - Google Patents

Description

[Detailed description of the invention] This invention is a braking device for an integrating wattmeter, in particular, high coercive force anisotropic permanent magnets extending oppositely from both ends of a pair of magnetic yokes, and a special structure between these permanent magnets. The present invention relates to a braking device having a temperature compensation device provided therein.

Inductive electromechanical wattmeters generally include an electromagnetic unit having a voltage section and a current section connected to an electrical load for measurement of AC electrical energy consumption.

The interaction of the magnetic flux from the electromagnetic unit with the eddy currents induced in the rotatable conductive instrument disc by the magnetic flux generates a drive torque acting on the disc.

Another common and basic element of a power meter is a magnetic damper.

A unidirectional, or DC, braking flux imparts a braking torque to the disc that is proportional to the disc speed.

The required braking and driving torques are balanced so that each revolution of the disc is proportional to the expected number of watt-hours of power consumption.

The damping flux is typically provided by a permanent magnet and directed through the air gap containing the instrument disc.

The amount and density of the braking torque are determined by the strength of the permanent magnet, the position of the braking magnetic flux with respect to the center of the disk, the area and density of the braking magnetic flux entering the disk, and the length of the air gap.

Keeping the braking flux constant is the main condition.

Eddy currents induced by the permanent magnet magnetic flux interact with the magnetic flux in a manner that resists the driving torque in a so-called square law relationship.

This relationship causes the magnetic flux to decrease in proportion to the square of the air gap length.

Keeping the damping torque induced by the damper constant is important for accurate measurement of the instrument.

Therefore, to maintain effective operation over a very long lifetime despite environmental changes such as widely varying temperatures and sometimes severe shock and vibration,
The damper air gap must be maintained at a constant minimum size when the magnetic flux is constant.

In addition, when using high-energy generating permanent magnets such as cobalt-rare earth element magnets, if the magnets are placed facing each other to form an air gap during assembly of the damper device, high coercive force and high anisotropy can be achieved. Due to their magnetic properties, they attract each other.

Air gap reduction due to mutual magnetic attraction must be avoided to maintain stable and accurate calibration of the instrument.

The damper device requires adjustment means to calibrate the braking torque.

This adjustment means is called full load adjustment in the technical field of integrating power meters.

. Such adjustments are made by changing the position of the braking flux relative to the center of the disk or by changing the amount of air gap flux by magnetic shunting.

The previous method has two effects: increasing the braking torque by moving the braking magnetic flux farther away from the center of the disc to increase the leverage, and increasing the braking torque by increasing the speed at which the disc's braking magnetic flux is cut. positioning is required.

In many magnetic damping systems, two or double lug gaps are used, so their positioning must be done not only with respect to the two effects described above, but also with respect to the interaction of the braking torque of the respective air gap fluxes. .

The second adjustment method often uses a soft magnet screw that changes the reluctance of the return path of the permanent magnet flux.

Temperature compensation of the magnetic damper device is also necessary so that the damping flux through the air gap remains constant.

Permanent magnetic materials typically used in damper devices have negative temperature coefficients and decrease in strength as temperature increases.

In the field of integrating power meters, this compensation is called class ■ salinity compensation.

Temperature-responsive magnetic shunts, such as those with negative temperature characteristic permeability, are typically used to shunt large amounts of air-gap magnetic flux at low temperatures and small amounts of it at high temperatures.

proper positioning, size and shape of the temperature compensator;
Proper selection of the properties of the compensator material is necessary.

The temperature compensator will typically be placed in parallel (as a shunt) adjacent to the direct path of the braking flux, and thus in the path of the stray or leakage flux surrounding the air gap.

When using permanent magnet materials with a high degree of directionality and anisotropy, such as cobalt-rare earth magnetic materials, a conventional temperature compensator adjacent to the main flux path captures changes in the magnetic flux and It is often not effective enough to change the

It is also particularly desirable that the magnetic damper device be configured to be most effective by minimizing the amount of stray or leakage magnetic flux typically inherent in the high reluctance path of the air gap.

Many of the above-mentioned characteristics and conditions for damper devices of wattmeters are shown in the patents listed below.

U.S. Patent No. 1843518, U.S. Patent No. 2309414,
Nos. 2,832,932, 3,173,067 and German Patent No. 804,694 disclose a permanent magnet damper device including a U-shaped magnetic yoke that serves as a main flux return path for the magnetic flux passing through opposing magnetic pole faces forming an air gap. Are listed.

No. 3,173,067 shows a temperature compensation device forming one of the pole faces in order to change the distribution of the braking flux instead of shunting a portion of it from the air gap.

In US Pat. Nos. 2,309,414 and 2,832,932, the stray flux portion of the permanent magnet flux is shunted by a temperature compensator mounted on the end or side of a permanent magnet with pole faces directing the flux into the air gap.

German Patent No. 804,694 discloses a thermally expandable temperature compensation device for changing the size of the air gap as the temperature changes.

U.S. Pat. No. 4,030,031 discloses a damper device that uses a pair of high coercivity anisotropic permanent magnets with double air gaps and made of cobalt-rare earth magnetic material.

U.S. Patent No. 1722756, U.S. Patent No. 1734199,
Same No. 1945523, Same No. 2605301, Same No. 3
No. 054953 shows a single U-shaped or C-shaped magnetic compensator shunt for shunting stray or leakage magnetic flux from the air gap of a damper device.

All of these last-mentioned patents include magnetic materials made of a magnetic material with a negative coefficient of magnetic permeability and placed on the sides of permanent magnet poles to increase the branching of the magnetic flux at low temperatures and to increase the branching of the magnetic flux at high temperatures. Contains a magnetic shunt to reduce the

In US Pat. No. 1,734,199, a U-shaped magnetic compensator is provided on the side of the permanent magnet in order to vary the shunted magnetic flux in response to changes in the rotational speed of the instrument disc rather than to changes in temperature.

The purpose of this invention is to obtain a magnetic braking device for an integrated power meter, which has a simple structure and can efficiently shunt magnetic flux and maintain the air gap at a predetermined value.

According to this invention, an improved magnetic braking device for an inductive power meter has a U-shaped flat magnetic bar forming a magnetic yoke member, and the magnetic braking device has a U-shaped flat magnetic bar forming a magnetic yoke member. A pair of permanent magnets with high coercive force and high anisotropy are provided that protrude from the center.

The magnetic pole face of this permanent magnet guides the braking magnetic flux through the air gap.

This air gap is of a minimum length that remains constant in order to reduce magnetic losses when the magnetic flux generates a braking torque imparted to an instrument disc that can rotate within this air gap.

A single piece temperature compensator extends between and over the pole faces to form a temperature sensitive flux shunt extending parallel to the air gap and parallel to the main flux return path through the yoke member.

In one preferred embodiment of this invention, a predetermined braking torque is generated by a braking magnetic flux guided from a cobalt rare earth element permanent magnet through a single air gap.

By placing the end of the one-piece temperature compensator on the pole of the permanent magnet, highly directional magnetic flux is effectively shunted therefrom.

Depending on the location of the temperature compensator and its inherent length and/or elasticity, the permanent magnet may be placed before or after final assembly to counteract the magnetic attraction of the permanent magnet, which may cause variations in the size of the air gap. Press it against the inner surface of the yoke member so as to maintain the correct size and coaxial position.

In a preferred embodiment of the invention, the temperature compensator provides the permanent magnet pole face with a magnetic permeability having a negative temperature coefficient and an elastic force to properly maintain the permanent magnet in a predetermined position at a predetermined spacing. It is made of a long and stiff U-shaped strip of nickel steel magnetic material.

In one preferred embodiment, the temperature compensator is formed with right-angled edges that engage the sides of each permanent magnet to prevent lateral movement.

In another form, an opening is provided in the surface of the temperature compensator that contacts the pole face, exposing a predetermined portion of the permanent magnet pole face, and dividing the magnetic flux passing through the pole face into one through the compensator and one directly into the air gap. Proportionate distribution.

One leg of the yoke member forms one of two parallel magnetic paths in the main flux return path, the other magnetic path being made of soft magnetic material and adjacent to said one yoke leg. Includes a full load adjustment screw that can be screw mounted.

In yet another version of the invention, the temperature compensator has a general U-shape, with a magnet held at its outer end, behind which it comes into contact with the inner surface of the yoke.

This configuration adds a magnetic flux distribution parallel to the main magnetic flux return path.

The general features of this device include a pair of permanent magnets made of high coercivity, high anisotropy magnetic material, protruding from both parallel ends of a soft magnetic U-shaped yoke member, and and extending over the magnetic pole faces of the permanent magnet to form a temperature-compensated magnetic shunt continuous with and parallel to the main magnetic flux path, and further forming an air gap of a predetermined size between the magnetic pole faces of the permanent magnet. A new and compact magnetic braking device is provided with a temperature compensation device that can be removed from a single component.

This braking device can be easily and efficiently assembled into the non-conductive frame of the power meter using die-casting, or between separate housings that can be attached to this frame. The size of the air gap is maintained accurately throughout the process.

Due to the high energy generation properties of permanent magnets, including the properties of hard permanent magnets with high residual magnetism, this braking device is able to withstand high voltage shocks and surges that sometimes occur on conductors connected to integrated wattmeters. It has a large resistance to demagnetization.

In this braking device, and in the fully assembled form of the billing wattmeter, this permanent magnet configuration allows the braking device to be magnetized during assembly and die-cast into a non-conductive frame. They are easy to demagnetize after being applied and can have precisely calibrated values that provide a predetermined braking flux.

The high magnetic flux densities produced by permanent magnets enable the use of small permanent magnets and correspondingly small magnetic yokes and temperature compensation devices, which are desirable for compact wattmeter construction.

The highly directional permanent magnet flux avoids the use of expensive magnetic shielding to prevent interaction between the wattmeter electromagnetic drive flux and the magnetic bearing flux.

Another feature of the invention is that it extends within the air gap space and within the space surrounded by the U-shaped yoke member to hold the temperature compensator in place while at the same time providing a defined gap in the air gap between the pole faces of the permanent magnet. It is a thermally responsive magnetic shunt temperature compensator with a bracket support that maintains its size.

Other features and advantages will become apparent from the drawing and the detailed description below.

FIG. 1 shows an inductive power meter 10 made of a non-magnetic die-cast material, such as aluminum, and including a frame 12 to which the various actuating parts of the meter are mounted.

This power meter is of the type having various meter components as described in US Pat. No. 3,309,152.

In order to obtain a better understanding of the invention, reference may be made to the aforementioned patents for details on the above briefly mentioned aspects of the instrument.

A rotatable and conductive disk 14 is supported on a vertical rotating shaft 16 supported by a magnetic bearing device.

The upper and lower bearing supports 18 and 20 are constructed as described in U.S. Pat.
93086 and 3810683, it is supported by a frame 12.

The electromagnetic unit described in the above-mentioned patent No. 3309152 includes a voltage section having a voltage coil wound around an E-shaped laminated core, and a current section having a pair of current coils wound around a C-shaped core. It is.

These voltage and current sections direct the AC drive magnetic flux through the air gap of the electromagnetic unit and the disk 14.

As is well known in the field of integrated wattmeters including this meter 10, a driving torque is generated in the disk 14 by the interaction between the eddy current and the driving magnetic flux that induces the eddy current.

A magnetic braking device 30 constructed according to this invention and supported by the frame 12 extends above and below both sides of the disc 14, and the braking magnetic flux directed to the disc thereby provides a braking torque due to eddy currents opposing the driving torque.

The magnetic braking torque is matched to the drive torque so that the rotation of the disc 14 and its axis of rotation 16 is proportional to the consumption of electrical energy to be measured by this instrument 10.

By means of a dial recorder outlined by a dashed line 32 as disclosed in the above-mentioned patent No. 3,309,152,
The rotation of the shaft 16 is integrated and the electrical energy consumption is indicated on the dial in kilowatt-hours, as is well known in the art.

The magnetic brake device 30 is also shown in perspective view in FIG. 3 and includes a U-shaped magnetic yoke member 34 and a pair of permanent magnets 36,38.

The permanent magnets 36 and 38 protrude from the inner surfaces of both ends of the yoke 34 and face each other with the disk 14 in between.

A single temperature compensator 40 extending over the pole faces of these opposing permanent magnets 36,38 resides within the space surrounded by the yoke 34 and extends between the two pole faces, as will be described in more detail below. A continuous magnetic path is formed between them.

The above-mentioned components of the magnetic braking device 30 are preferably housed in a cavity 42 formed in a forwardly projecting protrusion 44 of the die-cast frame 12.

Alternatively, the brake device can be removably attached to the frame, as described below in connection with FIGS. 7 and 8 and in U.S. Pat. No. 3,688,192.

This patent No. 3,688,192 describes a magnetic braking device consisting of a pair of rod-shaped permanent magnets housed in an aluminum die-cast unit for assembly into the frame of a multiphase integrated wattmeter.

Cavity 42 is sized, positioned, etc. to hold brake device 30 in a predetermined position for directing the brake magnetic flux to disc 14 .

As stated in the said patent No. 3309152,
If the brake device 30 is installed in the cavity 42 formed by the frame 12, the brake device 30 is housed in the cavity of the frame in a suitable manner, such as in the manner shown in U.S. Pat. fixed within the cavity.

In these two patents, a liquid material 46 is injected into the space between the brake device 30 and the inner surface of the cavity 42 and allowed to harden.
is disclosed.

Near the cavity 42 of the protrusion 44 of the frame is a threaded hole 4 into which a magnetic flux adjustment member, such as a full load adjustment screw 48, is inserted.
7 is provided.

Details of the magnetic braking device 30 including its housing and frame 1
When viewed from 2, it shows a U-shaped magnetic yoke member 3.
4 is a flat rod made of soft magnetic material (non-permanent magnet).

A permanent magnet 36 is placed at the outer end of the flat inner surface of the first leg 50 of this yoke 34.

A first leg 50 and a second leg 54 parallel thereto are connected by a curved portion communicating between them, and the yoke 34 is connected thereto.
A closed end 52 is formed.

A permanent magnet 38 is placed at the outer end of the flat inner surface of the second leg 54 such that the two magnets 36 and 38 face each other.

A full load adjustment screw 48 is provided parallel to the leg 54 and offset from its center.

This screw 48 is made of soft magnetic iron and is movable back and forth along the longitudinal axis of the leg 54 within the projection 44 of the frame.

Legs 54 are somewhat thinner than the rest of yoke 34 so that the magnetic flux passing through the yoke will cause the yoke to saturate even when legs 50 and closed end 52 are not.

This makes it possible for the screw 48 to change the main magnetic flux passing through the yoke 34.

The lengths of legs 50 and 52 are chosen such that the permanent magnets overlap at a predetermined radial distance from the center of disk 14.

The lengths of legs 50 and 54 are also selected such that temperature compensator 40 is housed within the space enclosed by their inner surfaces.

This will be discussed further later.

Permanent magnets 36 and 38 are generally rectangular in shape with substantially the same dimensions, with north and south poles extending from legs 50 and 54 of yoke 34.
are placed in series relationship at each end.

Permanent magnets 36 and 38 form pole pieces with faces 56 and 58 adjacent to yoke legs 50 and 54 and sandwiched between respective pole faces 60 and 62 to form instrument disc 14 as previously described.
The magnetic flux is sent out to the rotating air gap 64.

Rectangular permanent magnet 36 with back-to-back sides parallel to each other
and 38 are made from a permanent magnet material with high coercive force and high degree of anisotropy, and have strong force and high density of directional magnetic flux.

Thus, the magnetic flux exiting the pole face 60 travels virtually straight through the air gap 64 to the pole face 62 without following any lateral stray or leakage flux paths from the air gap 64.

A predetermined portion of the pole face flux is shunted through the temperature compensator 40.

Here, the high coercive force and high anisotropy permanent magnet material refers to U.S. Pat.
The present invention includes cobalt-rare earth intermetallic compounds or alloys containing cobalt and a plurality of rare earth metals as described in No. 5945 and No. 3802935, and cobalt rare earth element permanent magnet materials corresponding thereto.

The high coercivity and high anisotropy magnetic material is characterized by being a hard magnetic material that has high resistance to demagnetization.

The magnetic damping device of the wattmeter must withstand severe demagnetization effects caused by transients and high current surges appearing on power transmission lines, such as those caused by lightning.

Magnetic brake system 30 using a high coercivity, high anisotropy magnetic material, such as a cobalt-rare earth magnetic material, can withstand higher current surges than permanent magnetic materials traditionally used in brake systems.

The construction of the permanent magnets 36 and 38 allows the magnets to be magnetized to a predetermined calibrated flux value after incorporating these blocks of magnetic material into the magnetic damping device 30 and attaching the device to the frame 12. becomes possible.

This is particularly advantageous in the production of wattmeters, since the magnetic force of the permanent magnet attracts a considerable amount of magnetic particles and associated foreign matter that are difficult to clean later.

Typically, magnetic damping device 30 is attached to frame 12 with blocks of permanent magnetic material 36 and 38 substantially demagnetized.

A unidirectional electrical energization source causes magnetization of the permanent magnet with a predetermined polarity.

After the initial magnetization has taken place, the magnetism is reduced to the desired value, as is known in the art.

This degaussing is referred to in the art as sockdown and is described, for example, in US Pat. No. 2,668,275.

By using the high coercivity anisotropic permanent magnet materials described herein, the initial magnetization may provide the desired value without the need for knockdown.

Next, the temperature compensator 40 shown in FIG. 3, which is an important element of this invention, will be described in more detail.

The temperature compensator 40 includes integral U-shaped legs 70, 72 located inside and parallel to the magnetic yoke member 34, and an arcuate closed end 74 connecting them.

The temperature compensator 40 is made of a strip of magnetic material with a magnetic permeability of negative temperature coefficient, for example a nickel-iron alloy containing approximately 30% nickel.

The thickness of this board is 0.010 to 0.050 in (
0.0250.130cm).

The combination of the U-shaped shape, the hardness and strength of the nickel-iron magnetic material, and the above-mentioned thickness results in a structure with high strength and low elasticity utilized in this invention.

The temperature compensator leg 70.72 extends over and covers the pole face 60.62 of the permanent magnet 36.38.

The opposite edges of the temperature compensator are bent outwardly at substantially right angles to the flat body to form opposite lips 76.
．． 78 is formed.

These lips 76,78 engage respective opposite sides of the permanent magnet 36,38.

The permanent magnets 36 and 38 are pulled apart from each other by the strong force of the temperature compensator and pressed against the inner surface of the yoke legs 50,54.

Permanent magnets 36, 38 are prevented from lateral movement by lips 76, 78 and held coaxially facing each other.

The temperature compensator 40 itself is thus held in place by engagement with the permanent magnets 36,38.

The temperature compensator 40 thus forms a temperature responsive magnetic shunt and further directs the permanent magnets 36, 38 to the yoke legs 50.
．． 54 and place it in a predetermined position by pressing it against the inner surface of the cavity 64.
maintain that predetermined gap.

The effect of this magnetic braking device 30 is that the permanent magnets 36 and 38 emit magnetic flux from their magnetic pole faces, and this is the first braking magnetic flux.
It is guided to an instrument disk 14 shown in FIG. 2 and FIG. 2 to provide a predetermined braking torque.

The path of the braking magnetic flux exits one pole face, for example, the pole face 60, passes through the portion of the leg 70 of the U-shaped temperature compensator 40 that overlaps with the pole face 60, the air gap 64 in which the disk 14 is placed, and the leg 72 of the compensator. It reaches the magnetic pole face 62.

The main return path of this braking flux proceeds from the north pole face 58 of the magnet 38 to the yoke end 52.

At leg 54, a portion of the main magnetic flux is divided and directed to full load adjustment screw 48.

The main flux return path continues through the closed end 52 and leg 50 of the yoke to the south pole face of the magnet 36.

Pole face 60 also shunts a portion of the magnetic flux through compensator leg 70 , compensator closed end 74 , and leg 72 to pole face 62 .

The magnetic flux in this shunt therefore flows parallel to and opposite to the main flux path through the yoke.

This configuration has very high efficiency because the magnetic paths are concentrated inside the yoke member 34.

Since the magnetic flux of a permanent magnet is highly directional due to its anisotropic magnetic properties, placing a compensator on the pole face is very effective in controlling the braking flux entering the instrument disc through the air gap. be.

The negative temperature coefficient of magnetic permeability of the temperature compensator material increases the amount of magnetic flux passing through the temperature compensator 40 as the temperature decreases, and reduces the amount of magnetic flux that is shunted as the temperature increases.

This cancels out the negative temperature magnetic properties of the permanent magnets 36 and 38, and keeps the braking magnetic flux in the air gap 64 constant.

Due to the supporting action of the temperature compensator 40, the size of the air gap is kept constant in a unique manner with the above-mentioned strong forces.

Since the yoke member 34 is made of a soft magnetic iron material and has low strength and no temperature compensator bias strength, if the permanent magnets are directly attached to the ends of the legs 50 and 54 of the yoke member, the gap between the magnets is The size of the void is changed by the suction force.

Since the magnetic damping device 30 is intended to be housed and fixed in a separate housing, i.e. in the cavity 42 of the die-cast frame 12, its final assembled configuration will ensure that the damper device 30 is will be maintained with a gap length of

However, due to the shape and location of the permanent magnet, it is not always possible to effectively cover the sides of the permanent magnet with die-cast material or another fixed material.

Therefore, even within the cavity 42 or the housing, the attached magnet is continuously held with a predetermined gap due to the elasticity of the temperature compensator 40.

Also, before the magnetic damping device 30 is attached to the cavity 42, the air gap is maintained open by a temperature compensator as previously described.

4 and 5 show two temperature compensators 90, 92 which are alternative embodiments to the temperature compensator 40 of the present invention.

Like the temperature compensator 40, these also have a U-shape and are provided with lips 76,78.

In the temperature compensator 90, an opening 94,96 is provided in its leg 70,72 when the shunting effect of the compensator is greater than necessary.

These openings 94 , 96 expose a predetermined area of the pole faces of magnets 36 and 38 and shunt a lesser amount of magnetic flux from the pole faces than is shunted by temperature compensator 40 .

Therefore, part of the magnetic pole surface magnetic flux directly enters the air gap, another part passes through the temperature compensator and enters the air gap, and the remainder flows through the shunt.

The temperature compensator 92 shown in FIG. 5 also generally corresponds to the U-shape of the temperature compensator 40.

The single window 94 , 96 in each leg 70 , 72 of the temperature compensator 90 is replaced by a plurality of openings 104 in each leg 70 , 72 of the temperature compensator 92 .

An outwardly bent lip 76.78 is provided which corresponds to the lip 76.78 of the temperature compensator 40.

Legs 70. Tabs 106 and 108 are formed at the free end of groove 72.

These tabs 106, 108 engage the ends of the permanent magnets 36, 38 to hold the magnets in place and prevent them from sliding out of the yoke legs 50, 54.

6 to 8 show a magnetic braking device 120 according to yet another embodiment of the invention.

FIG. 6 shows the magnetic braking device 12 taken out from the housing.
0, and FIGS. 7 and 8 show the same magnetic brake device 120 removably contained within a housing 122.

This housing 122 replaces the frame projection 44 with the cavity 42 of FIG.

In FIG. 8, an integrated power meter frame 123 is a modification of the frame 12 that extends above and below the disk 14 in the normal operating position.
A housing 122 is mounted on top with a magnetic braking device 120.

Before discussing further about housing 122, magnetic brake system 120 will now be described.

Magnetic damping device 120 corresponds to magnetic damping device 30 described above, except that temperature compensating device 40 is replaced by a modified temperature compensating device 124.

Thus, the magnetic yoke member 34, the permanent magnets 36 and 38, and the full load adjustment screw 48 are the same or comparable to those of the magnetic brake system 30.

Temperature compensator 124 is temperature compensator 40.90.92
It is made of a strip of magnetic material with a magnetic permeability of the same negative temperature coefficient as .

Two legs 126, 128 of U-shaped temperature compensator 124
and a closed end 130 that connects these.

As shown in broken lines in FIG. 7, the U-shaped flattened central portion 132 of the temperature compensator extends continuously from the rear end to the rear end of each of the magnets 36 and 38.
0.54 is engaged with the portion of the inner surface immediately behind the magnet 36.38.

Lips 134 and 136 are formed in the central portion 132 at approximately right angles, the edges of which are bent inward.

At the outer free ends of the lips 134 and 136 there is a lip 136.
Laterally extending flanges 138 and 140 are formed from the free ends of the holder to laterally extending flanges 142 and 144.

The pair of flanges 138 and 142 hold the permanent magnet 36 against the yoke leg 50 in a predetermined position.

Similarly, flanges 140 and 144 retain magnet 38 on the inner surface of yoke leg 52.

7 between flanges 138 and 142 and between flanges 140 and 14
4 are opened to expose the center part of the magnetic pole face, and flanges overlap on both sides of the center part of each magnetic pole face.

This allows the temperature compensator 90 to have windows 94, 96, 104, 105 for exposing a portion of the magnetic pole face.
In the same way as described for 92, the magnet holding function and the magnetic pole surface magnetic flux control function can be obtained.

The mutually extending lengths of these flanges determine the contact area between the pole face and the temperature compensator.

The temperature compensator 124 provides a large space behind the permanent magnets 36,38 in the yoke legs 50 and 52 to accommodate magnetizing and demagnetizing or knockdown devices.

Temperature compensator 120 creates a magnetic flux shunt in magnetic brake device 120 between legs 50 and 52 of yoke member 34 .

That is, the temperature compensator 120 causes the permanent magnets 36 and 3 to
A temperature compensation magnetic path is formed between the magnetic pole faces of 8 and between the inner surfaces of the yoke legs 50, 52 which contact the temperature compensation device immediately after the magnets 36, 38.

In a compensator of the type of temperature compensator 120, legs 50 and 52
Since a compensation shunt magnetic path is added between the temperature compensators 40 and 90.92, it is believed that a better temperature compensation effect can be obtained than that of the type of temperature compensator 40, 90.92.

The magnetic brake device 120 is housed in the housing 122 in a pocket 150 that matches the outer shape of the yoke member 34, which corresponds to the cavity 42 in FIG. 1, as shown in FIG.

The space between the yoke member 34 and the inner surface of the pocket 150, the space between the temperature compensator 120 and the respective U-half ends of the yoke member 34 is die-cast or filled with the curable liquid material 46 described above. .

The mounting flanges 154, 156 of the housing 122 are provided with notches 158, 160 into which screws are inserted.

Insert the full load adjustment screw 4 into the screw hole 162 of the housing 122.
8 is inserted.

The screws 48 can thus be accessed from the side of the frame as shown in FIG.

A housing 122 is shown in FIG. 8 attached to an instrument frame 123 along with a magnetic brake 120.

It should be understood that any of the magnetic braking devices shown as examples herein can be mounted as shown in FIG. 1 or FIG. 8.

The housing 122 is fixed to the frame 123 by screws 164 inserted into its notches 158 and 160, replacing the protrusion 44 in FIG. is performed to provide disk 14 with a calibrated braking flux that does not change with temperature changes.

[Brief explanation of the drawing]

Fig. 1 is a partially removed front view of an inductive integrated power meter equipped with a magnetic braking device according to an embodiment of the invention, Fig. 2 is a sectional view taken along line II-II in Fig. 1, and Fig. 3 is a sectional view taken along line II-II in Fig. 1. The figure is a perspective view of the magnetic braking device shown in FIG. 1, FIGS. 4 and 5 are perspective views of two embodiments of the temperature compensation device used in the magnetic braking device shown in FIG. 2, and FIG. 6 is a perspective view of the magnetic braking device. a perspective view of another embodiment of;
Fig. 7 is a front view with a part of the housing and the magnetic braking device shown in Fig. 6 housed therein removed, and Fig. 8 is a cross-sectional view of the housing shown in Fig. 7 attached to the instrument frame. be. 12... Frame, 14... Rotatable disk, 30... Magnetic braking device, 34...
Yoke member, 36.38...Permanent magnet, 40...
...Temperature compensator, 50,52...Yoke leg, 60°62...Magnetic pole surface, 64...
Air gap, 70.72... Compensator leg.

Claims (6)

[Scope of utility model registration request] (1) A magnetic braking device for an integrating wattmeter comprising a rotatable conductive disc, comprising a U-shaped magnetic yoke member having opposed legs extending on both sides of a rotation path of the disc; a pair of permanent magnets that protrude from the inner surface of the iron member and are in a predetermined spaced relationship with opposing magnetic pole surfaces that receive the disk and direct braking magnetic flux to the disk; and legs that extend on the magnetic pole surfaces of the permanent magnets. extending along the inner periphery of the magnetic yoke member to form a continuous magnetic flux shunt between these magnetic pole faces, so that a part of the magnetic flux from the magnetic pole face passes through the magnetic flux shunt, and the other and a substantially U-shaped temperature compensator whose part passes through the space between the magnetic pole faces. (2) The opposing legs of the temperature compensator are biased toward opposing magnetic pole faces of the pair of permanent magnets, so that the compensator and the pair of permanent magnets are placed on the magnetic yoke member. 2. The magnetic braking device for an integrated wattmeter according to claim 1, wherein the magnetic braking device is held in a predetermined position and the predetermined spacing relationship is maintained between the pair of permanent magnets by the temperature compensation device. (3) The pair of permanent magnets are made of a highly coercive and highly anisotropic permanent magnet material, have high directionality, and generate magnetic flux that is substantially free of stray magnetic flux in a direction transverse to the magnetic pole face. 2. The magnetic braking device for an integrated wattmeter according to claim 1, wherein the opposing legs of the temperature compensator are in contact with opposing magnetic pole surfaces of the permanent magnet. (4) The magnetic braking device for an integrated wattmeter according to claim 1, wherein the pair of permanent magnets are made of a cobalt-rare earth element permanent magnet material. (5) The magnet for an integrated wattmeter according to claim 1, wherein the opposing legs of the temperature compensator have a predetermined opening that exposes a predetermined portion of the magnetic pole faces of the pair of permanent magnets. Braking device. (6) The utility model registration claim set forth in claim 1, wherein the opposing legs of the temperature compensator extend from a position where they contact the opposing magnetic pole surfaces to a position where they contact the inner surface of the yoke member. Magnetic braking device for integrated wattmeter.