An elevator drive system (40) includes a permanent magnet (PM) synchronous electric motor (34) including a plurality of phases and a plurality of motor drives (55, 58) electrically connected to the PM synchronous electric motor. Each of the plurality of motor drives is operatively connected to a corresponding one of the plurality of phases. The plurality of motor drives is configured and disposed to deliver a torque current divided equally between each of the plurality of phases and independently deliver flux current to the corresponding one of the plurality of phases.

An arrangement for detecting bearing failures in an elevator system, which elevator system includes a hoisting machinery with a traction sheave on a rotary shaft, an elevator car, a counterweight and a hoisting element connected between the car and the counterweight and arranged to be moved by the a rotation of the traction sheave, and which arrangement includes at least a motion sensor for measuring rotation of the hoisting motor. The arrangement includes a signal processing unit connected to the motion sensor and arranged to process vibration signals originated in the bearings of the elevator system.

A semiconductor device according to an embodiment includes: a silicon carbide layer; a silicon oxide layer; and a region disposed between the silicon carbide layer and the silicon oxide layer and having a nitrogen concentration equal to or more than 1×10.sup.21 cm.sup.−3. A nitrogen concentration distribution in the silicon carbide layer, the silicon oxide layer, and the region have a peak in the region, a nitrogen concentration at a first position 1 nm away from the peak to the side of the silicon oxide layer is equal to or less than 1×10.sup.18 cm.sup.−3 and a carbon concentration at the first position is equal to or less than 1×10.sup.18 cm.sup.3, and a nitrogen concentration at a second position 1 nm away from the peak to the side of the silicon carbide layer is equal to or less than 1×10.sup.18 cm.sup.−3.

An elevator installation and a method for lubricating bearings in an elevator hoist machine of the elevator installation ensure that during start-up and subsequent running of the elevator hoist machine the bearings are provided with a mixed film lubrication or an elastohydrodynamic lubrication to optimize bearing life expectation.

A semiconductor device of an embodiment includes an element region and a termination region surrounding the element region. The element region includes a gate trench, a first silicon carbide region of n-type, a second silicon carbide region of p-type on the first silicon carbide region, a third silicon carbide region of n-type on the second silicon carbide region, and a fourth silicon carbide region of p-type sandwiches the first silicon carbide region and the second silicon carbide region with the gate trench, the fourth silicon carbide region being deeper than the gate trench. The termination region includes a first trench surrounding the element region, and a fifth silicon carbide region of p-type between the first trench and the first silicon carbide region, the fifth silicon carbide region same or shallower than the fourth silicon carbide region. The semiconductor device includes a gate electrode, a first electrode, and a second electrode.

A semiconductor device of an embodiment includes: a silicon carbide layer including a first silicon carbide region of n-type containing one metal element selected from a group consisting of nickel (Ni), palladium (Pd), platinum (Pt), and chromium (Cr) and a second silicon carbide region of p-type containing the metal element; and a metal layer electrically connected to the first silicon carbide region and the second silicon carbide region. Among the metal elements contained in the first silicon carbide region, a proportion of the metal element positioned at a carbon site is higher than a proportion of the metal element positioned at an interstitial position. Among the metal elements contained in the second silicon carbide region, a proportion of the metal element positioned at an interstitial position is higher than a proportion of the metal element positioned at a carbon site.

The subject-matter disclosed relates to a power control system (10) for a battery driven elevator; the power control system (10) comprising a DC battery (16) for providing electrical power to an electric motor (24) of the elevator system; and a power controller (22) including a power converter (26), an power inverter (28), and a DC intermediate circuit (30) connected in between the power converter (26) and the power inverter (28); wherein an output of the DC battery (16) is connected to the DC intermediate circuit (30).

A permanent magnet (PM) synchronous electric motor (34) includes a plurality of phases, and a plurality of motor drives (55,58) electrically connected to the PM synchronous electric motor. Each of the motor drives is operatively connected to a corresponding one of the plurality of phases. The plurality of motor drives is configured and disposed to deliver a torque current divided equally between each of the plurality of phases and independently deliver flux current to the corresponding one of the plurality of phases. A controller (44) is operatively connected to each of the plurality of motor drives to selectively control the PM synchronous electric motor, and a rescue module (120) operatively connected to the controller, the rescue module being configured and disposed to determine a failure of one of the plurality of motor drives and control the PM synchronous electric motor in a reduced operation profile employing remaining ones of the plurality of motor drives.

This disclosure relates to an electromagnetic brake configured to slow a deceleration rate of a passenger conveyer, such as an elevator car, during braking. In particular, this disclosure relates to a passenger conveyer system including the electromagnetic brake and a corresponding method. An example system includes a controller and an electromagnetic brake. The electromagnetic brake includes a disc configured to interface with a drive shaft, a spring, and a plate biased in a first direction into engagement with the disc by a bias force of the spring. The electromagnetic brake further includes an electromagnet selectively activated in response to a command from the controller to produce a magnetic field attracting the plate in a second direction opposite the first direction to partially offset the bias force of the spring. Further, when the electromagnet is activated, the plate engages the disc.

A semiconductor device according to an embodiment includes: a silicon carbide layer; a silicon oxide layer; and a region disposed between the silicon carbide layer and the silicon oxide layer and having a nitrogen concentration equal to or more than 1×10.sup.21 cm.sup.−3. A nitrogen concentration distribution in the silicon carbide layer, the silicon oxide layer, and the region have a peak in the region, a nitrogen concentration at a first position 1 nm away from the peak to the side of the silicon oxide layer is equal to or less than 1×10.sup.18 cm.sup.−3 and a carbon concentration at the first position is equal to or less than 1×10.sup.18 cm.sup.−3, and a nitrogen concentration at a second position 1 nm away from the peak to the side of the silicon carbide layer is equal to or less than 1×10.sup.18 cm.sup.−3.