Hitachi, Ltd.

Hitoshi Yamashita

Akira Ishibashi

Hiroshi Fujii

Satoshi Ibori

Izumi Ochiai

Hideo Uzuhashi

Takatsugu Kambara

Akio Suzuki

Shigeyuki Baba

Syuji Tomita

Mitsuo Akiyama

Youji Sekine

Katsuo Matsui

In a variable frequency power source unit, a series circuit of a contactless semiconductor switching element and a resistor is provided in parallel to a d.c. smoothing capacitor, and a control circuit is provided for receiving a signal for turning on the switching element selectively at any time after the power source is interrupted, thereby discharging the electric charge on the d.c. smoothing capacitor.

Inverter apparatus provided with electric discharge control circuit of

A method of manufacturing a fan guard from a plate member wherein inward slits, each having at least a radial slit section are formed in a first section of the plate member located between a central section and a ring-like section radially outwardly spaced therefrom of the plate member such that the radial slit sections extend from the central section to the ring-like section in circumferentially spaced relation to each other. Radially outward slits, each having at least an arcuate slit section, are formed in a second section of the plate member located between the ring-like section and an outer peripheral section of the plate member such that the arcuate slit sections extend from the ring-like section to the outer peripheral section in circumferentially spaced relation to other. Portions each extending between the adjacent two radial slit sections are bent to form louvers. The central, first and ring-like sections are offset from the outer peripheral section while rotating the central, first and ring-like sections relative to the outer peripheral section, to twist portions extending between the adjacent two arcuate slit sections to form louvers.

Method of manufacturing fan guard

Growing community of inventors

Yachiyo, Japan

Hitoshi Yamashita