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Construction and Operation 1. Speed of rotation All tables of model specificati

Construction and Operation 1. Speed of rotation All tables of model specifications refer to normal rotational speeds. If motor application requires speeds different from those mentioned, please consult motor manufacturer or its representative. 2. Charge pressure The minimum pressure required at the motor's inlet port is called the charge pressure. It is needed to guarantee continuous contact between the cam ring and the cam rollers, especially in applications where an external force rotates the motor. For each motor size the charge pressure depends on the actual speed and case pressure. The performance curves show the charge pressure figure at minimum back pressure and with no casing pressure. With hydrostatic braking the charge pressure must be increased 1 – 2 bar (15 – 30 psi). Simultaneously, sufficient oil supply to the motor inlet port has to be assured. Especially for open circuits during hydrostatic braking using a relief valve, be sure to compensate for the drain flow and the flushing of heated oil. 3. Back pressure In applications where the pressure in the return line is too low compared to the case pressure and actual speed, the motor may make extraneous noise in service. This is caused by the inertial force of the piston and the fact that the pistons and cam rollers tend to lose contact with the cam ring. This problem can be eliminated by increasing pressure in the return line as high as required charge pressure at current speed, which guarantees continuous contact between the cam ring and cam rollers. This back pressure must not be present at the motor ports during freewheeling. 4. Case pressure The recommended case pressure for standard motors is 0 – 2 bar (0 – 30 psi). The maximum intermittent pressure is 10 bar (145 psi). If the motor is not rotating, a static case pressure up to 40 bar (580 psi) is allowed. Requirements for charge and back pressure increase, if the case pressure rises. For freewheeling, case filling and for regulating the case pressure, a check valve with 0.1 – 2 bar (2 – 30 psi) opening pressure is usually placed in the drain line. If freewheeling is never used and the motor is below the level of oil in the tank, the drain line is connected directly to the tank. 5. Freewheeling To disengage the motor, both working lines (i.e. inlet line and return line) are to be connected directly to the tank. To ensure that the lines are completely without pressure they should not be connected together with lines from other hydraulic circuits if this can lead to pressure disturbances, nor should any components causing pressure peaks or increases be connected to them. In order to produce the freewheeling pressure in the case, a fluid must be supplied to the motor through case drain line "C" (1 - speed motors only). When 2 - speed motor is needed to freewheel it is recommended to use motor with 2 case drain lines (6th digit in order code = 1) and a fluid to produce free coupling pressure must be supplied to the motor case through additional case drain line "C1". A check valve with an opening pressure of 2 bar (30 psi) in the drain line regulates the pressure in the case. Limitation of pressure peaks in the case is accomplished by dimensioning the return lines and check valves to correspond with the maximum intended speed of the motors at the moment of engaging/disengaging. Under certain circumstances (e.g. with long length of pipe, high rotational speeds or high viscosity oil) it is recommended to connect an accumulator (with at least 1/4 nominal capacity of the motor) to the drain line "C" (1 - speed motor) or "C1" (2 - speed motor with 2 drain lines). The accumulator should be as close to the motor as possible. Hydraulic accumulators designed for storing low pressure are sufficient. At the moment of engaging or disengaging the need for increased charge pressure must be taken into account. Closed circuit For vehicles having several hydraulic motors, freewheeling can provide higher speed ranges, since the total pump output is divided between fewer working motors. A. Disengaging the motor (shifting to higher speed range) 1. Motors to be freewheeled are detached to form an independent free circulation circuit. 2. A path from the motor circuit to the reservoir is rapidly opened, after which the constant small pressure in the casing disengages the motor. 3. The system charge pressure must be maintained in the pump circuit throughout the shifting procedure. 4. While shifting speed ranges, the sum of the displacement of the motors in operation changes gradually. The pump delivery is to be adjusted manually or automatically as required. 5. To avoid jerking during alteration of the pump delivery, the pump lines must be softly throttled. B. Engaging the motor (shifting to lower speed range) 1. Disengaged motors are brought into operation by connecting the "A" and "B" ports back into closed loop. 2. A charge pressure is rapidly applied to this circulation, forcing the pistons into motion. The charge pressure must be high enough to cover the pressure losses in the free circulation circuit as well. 3. The motors are connected to the same circuit as the pump. 4. The pump delivery is adjusted as required. Jerking can be avoided in the same way as when disengaging. 5. If the charge pump is too small, an accumulator is required to maintain the charge pressure. Accomplishment of the above is made easier by motor manufacturer's valves, which perform all the required operations except for modulating pump delivery. Some Black Bruin motors are equipped with mechanical freewheeling springs. These motors are freewheeled automatically when the motor's working lines become non-pressurized. However, a rapid disengaging requires an increase in case pressure. 3 6. Short circuiting connection Short circuiting connection is used, if the motor is required to rotate by an external force faster than the circuit flow is capable to supply. In such case motor outlet oil must be connected to the motor inlet port. Max. allowed short circuit speed is 1.5 times max. speed of the motor. The required charge pressure is easily regulated with back pressure in the return line. Simultaneously flushing with fresh fluid must be insured for proper cooling. 7. Permissible external loads The figures given in the tables refer only to non-simultaneous radial and axial loads. If applications with high combined radial and axial loads exist, please consult motor manufacturer or its representative to determine maximum permissible loading. The maximum permissible shaft loads depend on the loading point. For exact data see shaft load curves (see page 6). 8. Wet multi-disc brake The wet multi-disc brake is basically a parking brake, but in certain cases it can also be used as an emergency brake. (Not recommended to use as service brake. When used as a service brake consult motor manufacturer or its representatives.) The minimum pressure to release the spring operated brake is shown in the performance data page, however, the operating pressure used may be not higher than 30 bar (435 psi). The brake has internal leakage (max. 0.5 l/min) and this has to take into consideration, while designing the brake release system. Notice that EP, HD and some anti-wear additives in oil can cause remarkable reduction of brake torque. 9. Operation temperature The maximum allowed continuous operating temperature is 70˚C (160˚F) and the maximum intermittent value is 85˚C (185˚F), if the oil viscosity does not fall below 15 cSt. The lowest permissible operating temperature for a standard motor is -35˚C (-31˚F). When starting the motor, the difference between the motor and oil temperatures must not exceed 60˚C (140˚F). To avoid thermal shocks at low temperatures we recommend the following measures: - Run the motor at first with a low speed, unloaded. Gradually increase the speed and loading. - Below 0˚C (32˚F) avoid disengaging and engaging of motors when the vehicle is moving and the drain line is cold. 10. Oil requirements The mineral oil used should meet the following requirements: - The viscosity index must be at least 100. If the oil contains additives improving the viscosity index, the effect of these ought to be as permanent as possible. The oil is to maintain the required viscosity throughout its service life. - The minimum permissible viscosity is 15 cSt. - The maximum viscosity is determined by the specifications of the system pump. - The recommended viscosity range at operating temperature is 25-50 cSt. In slow use, a higher viscosity oil can be used. - To obtain maximum service life of both oil and entire system, oil temperatures exceeding 70˚C (160˚F) are to be avoided. - Oil additives must conform to the API – classification for SC motor oils. Hydraulic oils and SC, SD, SE and SF motor oils are recommended. Fire resistant fluids HFB and HFC or similar may be used under certain circumstances. Please always consult motor manufacturer or its representative before using these fluids. 11. Filtration Required cleanliness level: ISO 4406 uploads/Industriel/ bbc-designguide.pdf