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Published 05/16/2019

Gate turn-off thyristors (GTO)

Production of GTOs started in the mid1980s. A GTO is a thyristor that can be turned off by applying a current to the gate in the reverse direction to that required to turn it on.

GTOs are optimized for low conduction losses. The typical on-off switching frequency is in the range of 200 - 500 hertz for most applications. GTOs are, by nature, relatively slow switches.

Typical transition times from on to off state and vice versa are in a range of 10 - 30 microseconds. All GTOs require protective networks called "snubbers" for turn-on and turn-off. The turn-on snubber circuit, in essence an inductor, limits the rate of current rise. For turn-off, the GTO requires a device that limits the rate of voltage rise, in essence a capacitor.

All ABB GTOs are press-pack devices. They are pressed with a relatively high force onto heat-sinks which also serve as electrical contacts to the power terminals.

Asymmetric Gate Turn-off Thyristors (GTO)
Asymmetric GTOs are divided in two categories: Buffer layer and Standard. Buffer layer GTOs have exceptionally low on-state and dynamic losses. Fine pattern types (5SGF) are optimized for fast switching and transparent emitter (5SGT) for low on-state losses. The Standard GTOs have excellent trade-off between on-state and switching losses.

Darrah Electric is an authorized distributor for ABB. Click here to see our inventory or call our sales for questions or lead times at (216) 631-0912.