Ryobi D552HK English Manual - Page 10

OPERATION VARIABLE SPEED The variable speed switch delivers higher speed with increased trigger pressure and lower speed with decreased trigger pressure. Note: You might hear a whistling or ringing noise from the switch during use. Do not be concerned; this is a normal part of the switch function. DIRECTION OF ROTATION SELECTOR (FORWARD/REVERSE) See Figure 3. The direction of bit rotation is reversible and is controlled by a selector located above the switch trigger. With the drill held in normal operating position, the direction of rotation selector should be positioned to the left of the switch trigger for forward drilling. The drilling direction is reversed when the selector is to the right of the switch trigger. CAUTION: To prevent gear damage, always allow the chuck to come to a complete stop before changing the direction of rotation. To stop the drill, release the switch trigger and allow the chuck to come to a complete stop. NOTE: The drill will not run unless the direction of rotation selector is pushed fully to the left or right. Avoid running the drill at low speeds for extended periods of time. Running at low speeds under constant usage may cause the drill to become overheated. If this occurs, cool the drill by running it without a load and at full speed. TWO-SPEED GEAR TRAIN See Figure 4. The drill has a two-speed gear train designed for drilling or driving at LO (1) or HI (2) speeds. A switch is located on the side of the drill to select either LO (1) or HI (2) speed. When using drill in the LO (1) speed range, speed will decrease and unit will have more power and torque. When using drill in the HI (2) speed range, speed will increase and unit will have less power and torque. Use LO (1) speed for high power and torque applications, usually for drill bits larger than 3/8 in. Use HI (2) speed for fast drilling or driving applications, usually for drill bits smaller than 3/8 in. CAUTION: To prevent gear damage, always allow the chuck to come to a complete stop before changing gear speed. REVERSE ROTATION FORWARD ROTATION DIRECTION OF ROTATION SELECTOR (Forward/Reverse) HI (2) lo (1) Fig. 3 two-speed gear shift knob Fig. 4 10