Abstract: An electrical driving device has three permanent-magnet-excited rotors 3 whose shafts 3S extend through intersections S between a circle 4 and 120.degree. spaced-apart radii 5 which diverge from the centre M of the circle. Each of the cylindrical rotors 3 is associated with three stator poles 7.1, 7.2, 7.3, which are spaced from the cylinder circumference by air gaps 6. Three of these stator poles 7.1 which are situated within the circle 4 are connected by means of yoke irons J.sub.1. The stator poles 7.2 and 7.3 situated outside the circle 4 are connected in pairs via yoke bridges J.sub.2. These yoke bridges J.sub.2 are, in their turn, connected to yoke irons J.sub.3, which carry excitation coils 10. At their ends which are remote from the yoke bridges J.sub.2 all the yoke irons J.sub.3 are magnetically connected via a return yoke J.sub.4. The yoke iron J.sub.1, the stator poles 7.1, 7.2 and 7.3, the Yoke bridges J.sub.2 interconnecting them, the yoke iron J.sub.3 and the return yoke J.sub.

Abstract: A control circuit for controlling the speed and stopping time of an electronically commutated motor having a rotary drive member and a stator having at least one phase coil, electric power being supplied to the phase coils by current supply elements which are controlled by the control circuit to obtain a given phase voltage and a given load angle during operation. In response to a supplied stop signal the control circuit decelerates the drive member by controlling the phase voltage and load angle so as to produce a deceleration force which changes dependent on the speed of the drive member; there being a high speed range over which the deceleration force increases to a maximum value as speed is reduced; an intermediate speed range over which the deceleration force remains substantially constant at the maximum value as speed is further reduced, and a low speed range over which the deceleration force reduces as speed is still further reduced to a stop.

Abstract: In a D.C. motor having a position detector for detecting predetermined rotor positions and an electronic commutation circuit for connecting the stator coils to the power supply in a predefined cyclic order (and for disconnecting them) in dependence upon detected predetermined rotor positions, the no-load speed is limited by delaying the connection of a next stator coil in response to a new detection of a next one of the predetermined rotor positions, until a predetermined delay period has elapsed after a previous detection of another rotor position that lies a predetermined distance ahead of the newly detected rotor position.

Abstract: A ballast for powering a lamp at deep dim levels. Driving circuitry includes a feedback loop which compares a desired dim level to a signal representing actual lamp power consumption. The loop is closed once the signal representing actual lamp power consumption equals the desired dim level. During ignition, a switch in response to the lamp voltage reaching or exceeding a predetermined threshold opens the feedback loop. The feedback loop is closed once the lamp has been ignited. By closing the loop as soon as the lamp has been ignited, ignition flash is minimized.

Abstract: An electric micromotor comprising a stator winding, a rotor magnet (11) mounted for rotation about a rotor axis (13) and having permanent-magnet poles facing the stator winding, and electrical connection means for the electrical connection of the stator winding to a power source. The stator winding is formed by a cylindrical body (1) having an electrically conductive cylindrical wall (3) provided with longitudinal slots, which extend from an axial end face (15) of the cylindrical body over at least a part of the length of this body, to bound and form axially extending electrical conductors (5) for cooperation with the permanent-magnet poles. The conductors are mechanically interconnected by electrically insulating reinforcement means (19) at the location of the longitudinal slots.

Abstract: A power supply with improved power factor comprises a first rectifier circuit connected to an electric mains and which has first output terminals for supplying a first pulsating direct voltage. A buffer capacitor is connected parallel to the first output terminals and an inverter is connected to the buffer capacitor. A second rectifier circuit is connected to the mains and has second output terminals for supplying a second pulsating direct voltage. A flyback converter is connected to the second output terminals and has output terminals connected parallel to the buffer capacitor. The converter increases the power factor of the power supply and is operative to supply a maximum power which is substantially lower than the maximum power of the first rectifier circuit. The converter comprises a transformer with a primary winding and a secondary winding.

Abstract: The invention relates to a circuit arrangement for operating a lamp (LA), comprising means X for generating a current of alternating polarity, a load branch B coupled to the means X and provided with a series circuit Y comprisingterminals (K1, K2) for holding the lamp, which terminals are connected by means of first capacitive means C1, anda current sensor SEmeans I coupled to current sensor SE and to the means X for controlling the power consumed by the lamp.

Abstract: A tubular shaped device for insulating an electrical component such as, but not limited to, a dry film capacitor. Along one edge of the device is a rectangular shaped cutout for receiving radially extending leads of the electrical component. The electrical component is secured within the device by spreading the device open, placing the electrical component within the spread-open device, positioning the leads of the electrical component within the cutout and finally permitting the device to once again assume its tubular shape.

Abstract: A segment is magnetized by arranging it between two dies of a magnetizable material, which are armatures of an electromagnet and which each contact said segment along one of the cylindrical surfaces. In accordance with the invention, use is made of a die which comprises an element of a magnetizable material which leaves the longitudinal end portions of the piece to be magnetized partly uncovered, said die optionally being supplemented with elements of a non-magnetic material. The segment may be use in small-power motors, for example for use in cars.

Abstract: A ballast includes safety circuitry which senses lamp status through various phases of ballast operation. According to one feature, the ballast is prevented from supplying an output voltage upon initial energization of the ballast when a lamp is not present at the output terminals. The presence of a filament is sensed via a DC path extending through the filament heater windings of an output transformer. When the DC path is not complete, a control input, for example the power supply input of the ballast controller, is not provided with a voltage to start ballast operation. The DC path is also used to restart the ballast if a defective lamp is replaced with a good one. Over-voltage and capacitive mode detection is also disclosed to shut down ballast output upon lamp failure/removal.

Abstract: A flat electric motor comprises a rotor with a flat, permanent magnetic disc which is rotatable about an axis of rotation, and an electromagnetic stator with a stack of flat, electrically insulating supporting elements having first and second principal surfaces on which patterns of conductor tracks are provided such that there is formed a number of windings consisting of first and second coils arranged in a ring about the axis of rotation and which are formed by spirally extending conductor tracks on the first and the second principal surface of each supporting element. The coils which form part of one winding are electrically connected in series via connection tracks which a part of the conductor tracks, interconnections which extend between the first and second principal surfaces, and connection elements which connect connection tracks on different supporting elements of the stack to one another.

Abstract: A magnetic drive arrangement comprising a plurality of magnetically cooperating parts which are moveable relative to one another, one of the parts being connected to a drive shaft and one of the parts being stationary, the fields produced by the permanent magnets being modulated by soft-magnetic flux-carrying parts which include at least one toothed iron yoke, wherein structures are provided on both sides of the iron yoke to generate magnetic fields by means of permanent magnets at the sides facing the iron yoke, with the magnetic fields alternatively exhibiting north poles and south poles along the circumference.

Abstract: A capped electric lamp according to the invention comprises a lamp vessel (10) which is closed in a gastight manner and encloses a light source. The lamp vessel (10) is surrounded by a glass outer envelope (20) which is fastened at an end portion (21) to a housing (40) by means of a coupling member (30), which housing in addition supports a lamp cap (50). The coupling member (30) is made of metal, and the end portion (21) of the outer envelope (20) is fused to the coupling member (30). In the lamp according to the invention, the coupling member (30) is of a simple construction while nevertheless a blown outer envelope (20) can be used.

Abstract: A digital servo control with improved control accuracy, in which the arithmetical mean of a sequential series of n data words is used as a basis for the nominal value for a NOMINAL/ACTUAL value comparison to derive a setting signal. Depending on the value of the arithmetical mean, also intermediate values of adjacent quantization stages may thus be included and taken into consideration for control purposes.

Abstract: A piezoelectric sensor system according to the invention employs a piezoelectric actuator relay (20) having a piezoelectric element displaceable in response to an actuation voltage and contacts (23, 24) which open or close in accordance with the displacement of the element, wherein the actuator relay (20) is adapted to receive a force (L) to be measured against the displacement. This piezoelectric actuator relay (20) is supplied, by a driver circuit (60), with a varying voltage as the actuation voltage. The relation between the forces (L) and the activation voltages necessary for opening or closing the contacts (23, 24) has been stored in a memory (70). A processor (50) obtains a value of the force (L) based on a value of the actuation voltage at the instant of the opening or closure of the contacts (23, 24) and the relation stored in the memory (70).

Abstract: A ballast for powering a fluorescent lamp with filaments requiring preheating. Control circuitry within the ballast delays an ignitor from being turned on until the filaments have been sufficiently preheated. The control circuitry is isolated and thereby protected from the high voltage pulses of the ignitor by an optocoupler. A SIDAC employed in the generation of the high voltage pulses is not relied upon for sensing full arc discharge of the lamp. The breakover voltage of the SIDAC can therefore be set at a much lower than conventional level resulting in the generation of more high voltage pulses over a prefixed period of time.

Abstract: A circuit for operating a lamp includes supply input terminals for connection to a supply voltage source and a transformer provided with a primary winding L1 and a secondary winding L2. A first branch has terminals (N1,N2) for holding the lamp and connects a first end of the secondary winding L2 to a second end thereof. A second branch comprising a series circuit of a switching element (Q1) and the primary winding L1 interconnects the supply input terminals. A control circuit (SC1) is coupled to a control electrode of the switching element for generating a control signal for rendering the switching element conducting and non-conducting, and thus generating a first current in the primary winding L1 and a second current in the secondary winding L2. The second branch comprises a series arrangement of the primary winding, the switching element (Q1), and the terminals (N1,N2) for connection to the lamp. The total lamp current is controlled via the switching element which passes only a portion of the lamp current.

Abstract: An ignition scheme for starting a high intensity discharge lamp requiring energy in the form of ignition pulses to be provided to the lamp prior to and substantially throughout the glow load of the lamp. An ignitor includes a bilateral switching device such as, but not limited to, a SIDAC having a breakover voltage corresponding to the lamp voltage during the lamp glow mode. The ignition scheme substantially eliminates the lamp remaining in its glow mode for a prolonged period of time thereby minimizing the possibility of lamp destruction from damage to the lamp electrodes.

Abstract: A circuit arrangement for operating a high pressure discharge lamp includes input terminals for connection to a supply voltage source and an apparatus coupled to the input terminals for supplying an alternating lamp current to the high pressure discharge lamp. A device (III) is provided for generating a current pulse in each half period of the lamp current. This current pulse has the same polarity as the lamp current and is superimposed on the lamp current in the latter part of a predetermined fraction of the half periods of the lamp current. The circuit substantially suppresses flickering of the discharge arc during lamp operation.

Abstract: An axial flux induction motor has a stator and a disc-shaped rotor facing the stator with an air gap there-between. The rotor disc includes a first material of relatively high magnetic permeability and a second material of relatively high electrical conductivity, the first material being of higher specific gravity than the second material. The first material is in the form of an annular ring imbedded in or supported on one surface of the disc, opposite the surface thereof which faces the stator. The outer radius R.sub.1 of the annular ring and the outer radius R.sub.2 of the disc are related so that 1.2 R.sub.1 <R.sub.2 <1.6 R.sub.1. This achieves that at high rotational speeds the two disc materials will be subjected to more nearly equal centrifugal forces thereby making it feasible to operate at higher motor speeds.