1, according to the principle of work:
(1) Switch type lightning arrester:
Its working principle is that it exhibits a high impedance when there is no instantaneous overvoltage, but once it responds to a lightning overvoltage, its impedance mutates to a low value, allowing the lightning current to pass through. Devices used for such devices include: discharge gaps, gas discharge tubes, thyristors, etc.
(2) Limit pressure type lightning arrester:
Its working principle is that when there is no instantaneous overvoltage, it is high impedance, but with increasing surge current and voltage, its impedance will continuously decrease, and its current-voltage characteristic is strongly non-linear. Devices used for such devices include: zinc oxide, varistors, suppression diodes, avalanche diodes, and the like. Today's surge arresters are mostly limited pressure type.
(3) Shunt type or turbulence type lightning protector
Shunt type: In parallel with the protected device, it exhibits low impedance for lightning pulses and high impedance for normal operating frequency.
Turbulence: In series with a protected device, it exhibits a high impedance for lightning pulses and a low impedance for normal operating frequencies.
Devices used for such devices include: choke coils, high-pass filters, low-pass filters, quarter-wave short-circuiters, and the like.
2, according to use points:
(1) Lightning protection device : lightning protection device for AC power supply, lightning protection device for DC power supply, lightning protection device for special power supply (wind power, solar energy), etc.
(2) Signal lightning protectors : digital signal lightning protection devices, analog signal lightning protection devices, and antenna feeder lightning protection devices.
(3) Combination lightning arresters : SPDs that protect a variety of signals and power supplies at the same time, such as lightning protection devices that integrate video protection against lightning and power supply lightning protection at the camera end in the surveillance system. The lightning protection device that provides both Ethernet signal and power protection at the same time in communication.
3, according to lightning protection points:
Class B SPD: General nominal current is above 30KA. Switch type and pressure limiting type.
Class C lightning protector: The general nominal current is between 15~20KA, all of them are pressure limiting type.
Class D lightning arrester: Generally nominal current is between 5~10KA, all of which are pressure limiting type.
Forklift Mast Rollers are generally found running between the inner masts and four lift mast rollers run between the outer and the inner masts. The mast is located at the frontal part of a forklift and its purpose is to raise and lower loads. The mast rollers transforms the forces and moments that derive from the fork carrier, into the mast and into the frame. It is an extremely important component of the mast as it enables the vertical movement of the fork carriers, while maintaining its structural rigidity.
Mast rollers are available in two fitting series, HULR and LRQ. HULR series consists of two rows of contact Ball Bearings. Whereas, LRQ series consists of a single row of four point contact ball bearings. The bearings are structurally engineered to be capable of supporting great axial, radial, and moment forces. The rollers have crowned outside surface that consists of outer rings, which prevents edge loads, due to the possibility of a misalignment. While the inner roles are designed to be of a singular piece to be easily installed, which translates to cost savings.
Forklift Main Roller Bearing
Forklift Main Roller Bearing,Steel Roller Forklift Main Bearing,Bearing For Forklift Truck ,Roller Bearing For Forklift
Ningbo Ritbearing Imp & Exp Co.,Ltd. , https://www.nbbearing.de