ASME B30.17-2020 pdf – Cranes and Monorails (With Underhung Trolley or Bridge).
17-1.13.4 TroLLey and Bridge Brake Provisions
The general provisions outlined below apply to trolley and bridge brakes.
(a) Brakes shall be provided with means of adjustment to compensate for lining wear.
(b) Brake pedals, latches, and levers should allow release without the exertion of greater force than was used in applying the brake.
(c) Foot-operated brakes shall require an applied force of not more than 70 lb (310 N) to develop rated brake torque.
(d) Foot-operated brake pedals shall be so constructed that the operator’s foot will not readily slip off the pedal.
(e) Foot-operated brake pedals shall be so located that they are readily accessible to the operator at the controls.
(f) Foot-operated brakes shall be equipped with a means for positive release when force is released from the pedal.
(g) When provided, a parking brake shall
(1) be applied automatically or manually
(2) prevent horizontal motion of the trolley or bridge in accordance with the requirements of para. 17-1.13.2(a)(2) or para. 17-1.13.3(a)(2)
(3) not prohibit the use of a drift point in the control circuit
17-1.14.1 GeneraL
(a) Wiring and equipment shall comply with ANSI/ NFPA 70.
(b) The control circuit voltage shall not exceed 600 V for AC or DC.
(c) The voltage at pendant push buttons shall not exceed 150 V for AC or 300 V for DC.
(d) Where multiple-conductor cable is used with a suspended push-button station, the station shall be supported so that electrical conductors are protected from strain.
(e) Pendant control stations shall be constructed to prevent electrical shock. The push-button enclosure shall be at ground potential and marked for identification of functions.
U3 When equipment is used in hazardous locations as defined by ANSI/N FPA 70, modifications to these rules or additional safety requirements may be necessary. In these locations, cranes shall be designed and installed in a manner suitable for the conditions encountered.
17-1.14.2 Equipment
(a) Electrical equipment shall be so located or enclosed such that personnel will not be exposed to inadvertent contact with energized parts under normal operating conditions.
moisture, and they should be protected from dirt.
(c) Guards for energized parts, if provided, shall be constructed or located so that they cannot be inadvertently deformed so as to make contact with energized parts.
(d) Working space in the direction of access to energized parts that are likely to require inspection, adjustment, servicing, or maintenance, including all bridge- mounted control panel enclosures or switching devices, shall be a minimum of 30 in. (762 mm) from the surface of the enclosure or panel door. In addition, the work space in front of the enclosure or panel shall be at least as wide as the enclosure and shall be not less than 30 in. (762 mm) wide.
17-1.14.3 ControLLers
(a) Cranes not equipped with spring-return controllers, spring-return master switches, or momentary contact push buttons shall be provided with a device that will disconnect all motors from the line in the event of a power failure. The disconnect device shall not permit any motor to be restarted until the controller or master switch handle is brought to the OFF position, or a reset switch or power-on button is operated.
(b) Cab-Operated Controls
(1) Lever-operated manual controllers and master switches shall be provided with an OFF-position notch or latch. A spring return to the OFF position is acceptable.
(2) The operating handle for a manual controller or master switch shall be located within reach of the operator.
(3) The movement of the handle of each manual controller or master switch should be in the same general direction as the resultant movements of the load, except as shown in Figures 17-1.14.3-1 and 17-1.14.3-2.
(4) The arrangement of controllers or master switches should conform to Figures 17-1.14.3-1 and 17-1.14.3-2. Compass directions may be substituted for “Right—Left” and “Forward—Reverse” in Figure 17-1.14.3-3, and for the W, X, Y, and Z designations in Figure 17-1.14.3-4.
(c) Floor-Operated Controls.