摘要:
A multiphase electric motor control device includes: a bridge circuit including phase circuits each including a high potential side switching element, a low potential side switching element, and a current detector, a PWM control unit that outputs PWM signals to the switching elements; a control unit that acquires phase current values at a timing synchronized with a triangle wave; and a current value estimation unit that estimates a phase current value of one phase based on phase current values of other phases. In a case where an ON time of the PWM signal output to the low potential side switching element of the one phase from the PWM control unit is shorter than a predetermined time, the control unit acquires the phase current values which are detected by shifting the timing by using the current detectors of at least the other phases.
摘要:
A solid-liquid separator prevents wear of a self-priming liquid pump connected to a cyclone mechanism and a solid-liquid mixture can be purified at low cost. The separator separates sludge in the liquid by a cyclone in a separation portion directly or indirectly connected to a suction of the upstream side of the pump. The separation portion has a first and second cyclones with the first cyclone disposed in said second cyclone coaxially. A tank disposed under the cyclones collects separated from the liquid.
摘要:
A liquid pump has a sealing mechanism utilizing magnets. The sealing mechanism includes an annular rotating seal attached to the lower surface of a rotary base member fixed to the motor rotating shaft. Additionally, a flexible stationary seal is joined and separated with respect to the rotating seal. Movable magnets are disposed on the rotary base and are adapted to be displaced by centrifugal force due to a rotation of the rotary base member. A stationary magnet is disposed on the upper-surface side of a vertical sliding member to which the flexible stationary seal is fixed. The flexible stationary seal utilized has a cylindrical body. At the upper and lower end portions and the side surface portion, connecting portions to the stationary and movable members are formed. The middle portion has an elastic portion is formed on it.
摘要:
According to the package board of the present invention, each soldering pad formed on the top surface of the package board, on which an IC chip is to be mounted, is small (133 to 170 &mgr;m in diameter), so the metallic portion occupied by the soldering pads on the surface of the package board is also small. On the other hand, each soldering pad formed on the bottom surface of the package board, on which a mother board, etc. are to be mounted, is large (600 &mgr;m in diameter), so the metallic portion occupied by the soldering pads on the surface of the package board is also large. Consequently, a dummy pattern 58M is formed between conductor circuits 58U and 58U for forming signal lines on the IC chip side surface of the package board thereby to increase the metallic portion on the surface and adjust the rate of the metallic portion between the IC chip side and the mother board side of the package board, protecting the package board from warping in the manufacturing processes, as well as during operation.
摘要:
A recovery pump capable of reliably recovering floating oil and/or floating matter such as scum or the like while being significantly down-sized. A pump casing is provided in a lower section thereof with a suction passage and a discharge passage. The suction passage is horizontally arranged and has a suction opening and the discharge passage is horizontally arranged below the suction passage. The passages are arranged so as to communicate with each other through a through-hole and the discharge passage is provided therewithin right below the through-hole with an impeller, which is driven by a drive motor located on an upper section of the pump casing. The suction opening is provided with a recovery section for recovering the floating oil and/or floating matter.
摘要:
The present invention relates to a solenoid-operated valve for a thermally insulated piping having a thermally insulated outer periphery suitable for transporting low-temperature fluid, high-temperature fluid or the like and relates also to an attachment construction for the valve.Conventionally, with this type of solenoid-operated valve for a thermally insulated piping, since it is necessary to to increase a magnetic flux density of the solenoid coil by increasing the number of turns of the oil or the electric current to be applied thereto, there has been the problem of high production costs and running costs.In the case of the solenoid-operated valve for a thermally insulated piping according to the present invention, inside a heat-insulating layer (6) surrounding flow passages (7, 20, 21, 26, 33) in the form of a pipe, there is provided a fixed core (23) constituting a magnetic circuit between a solenoid coil (17) and a movable coil (18). Then, magnetic resistance between the solenoid coil and the movable core may be reduced, without entailing enlargement of the movable core and the production costs and the running costs may be reduced.
摘要:
The present invention provides a method of repairing the joint portions of an existing gas pipe by a repairing device which is movable inside the pipe under remote control. The repairing device can be moved into and out of the gas pipe through a work opening formed in an upper portion of the gas pipe by boring means with gas flowing through the pipe and free of the hazard of gas leakage. This reduces the labor required for forming the work opening to start the repair work and for restoring the work opening portion to complete the repair work, consequently assuring a shortened work period and a reduced cost.
摘要:
An air-conditioning apparatus for adjusting the direction and quantity of air comprises a duct device forming an air passage passing through the duct device, and an airflow adjusting device. The airflow adjusting device is made from a single thin plate and fitted to the duct device across the air passage to adjust a flow of air. Slits of predetermined patterns are formed on the airflow adjusting device to define a plurality of vanes which are integral to the airflow adjusting device. Functions for adjusting the direction and quantity of air are basically realized only with the single thin plate so that the material and manufacturing costs of the apparatus will be reduced, the transportation, installation and maintenance of the apparatus simplified, and angles of the vanes adjusted separately and freely.
摘要:
A polyphase electric motor control device stores a first threshold as a duty cycle at which noise caused by a high potential-side switching element starts to overlap a first measurement period, and a second threshold as a duty cycle at which time when a low potential-side switching element is switched from on to off is after an end of a second measurement period, makes a first judgment for comparing a maximum target duty cycle with the first threshold, and a second judgment for comparing a second greatest target duty cycle with the second threshold, measures a current in the first measurement period when the maximum target duty cycle is smaller than the first threshold, and measures a current in the second measurement period when the maximum target duty cycle is greater than the first threshold and the second greatest target duty cycle is smaller than the second threshold.
摘要:
In a magnetic pole direction detection device, a detecting target magnet is attached to a tip of a rotating shaft of the rotor. A magnetic detection unit outputs a detection signal which changes according to a change in a magnetic field. A magnetic pole direction calculation unit calculates a magnetic pole direction of a rotor based on the detection signal. A current detection unit detects a current flowing through each multiphase coil. A rotating magnetic field vector calculation unit calculates a vector of a rotating magnetic field based on magnitude of the detected current. A direction correction amount calculation unit calculates a direction correction amount based on a direction and magnitude of the rotating magnetic field calculated by the rotating magnetic field vector calculation unit. A magnetic pole direction correction unit corrects the calculated magnetic pole direction by using the calculated direction correction amount calculated.