Drum Hoists

Chapter 13 - Drum Hoists
Number	Topic	Rule of Thumb
13.01	Hoist Speed	The maximum desirable speed for a double-drum hoist with fixed steel guides in the shaft is 18m/s (3,600 fpm). Source: Peter Collins
13.02	Hoist Speed	The maximum desirable speed for a drum hoist with wood guides in the shaft is 12m/s (2,400 fpm). Source: Don Purdie
13.03	Hoist Speed	An analysis of the theory developed by ASEA (now ABB) leads to the conclusion that the optimum speed is a direct function of the square root of the hoisting distance. Applying the guideline of 50% and assuming reasonable values for acceleration and retardation leads to the following rule of thumb equation for the optimum economic speed for drum hoists, in which H is the hoisting distance.
		Optimum Speed (fpm) = 44H½ , where H is in feet
		Or, Optimum Speed (m/s) = 0.405 H½ , where H is in metres
		Source: Larry Cooper
13.04	Hoist Speed	Assuming reasonable values for acceleration gives the following rule of thumb equations for the design speed of drum hoists, in which H is the hoisting distance (feet).
		Design Speed (fpm) = 34 H^½ , hoisting distance less than 1,500 feet
		Design Speed (fpm) = 47 H^½ , hoisting distance more than 1,500 feet
		Source: Ingersoll-Rand
13.05	Hoist Speed	The hoist wheel rotation at full speed should not exceed 75 revolutions per minute (RPM) for a geared drive, nor 100-RPM for a direct drive. Source: Ingersoll-Rand
13.06	Hoist Speed	For a direct drive with a DC motor, 100-RPM is an optimum speed rather than a maximum speed. Source: Sigurd Grimestad
13.07	Hoist Speed	For a skip hoist, the acceleration to full speed should not exceed 1.0 m/s2 (3.3 fps2). For a hoist transporting persons, it should not exceed 0.8 m/s2 (2.5 fps2) as a matter of comfort to the passengers. Source: Sigurd Grimestad
13.08	Hoist Availability	With proper maintenance planning, a drum hoist should be available 19 hours per day for a surface installation, 18 for an internal shaft (winze). Source: Alex Cameron
13.09	Hoist Availability	A drum hoist is available for production for 120 hours per week. This assumes the hoist is manned 24 hours per day, 7 days per week, and that muck is available for hoisting. Source: Jack Morris
13.10	Hoist Availability	The total operating time scheduled during planning stages should not exceed 70% of the total operating time available, that is 16.8 hours per day of twenty-four hours. Source: Tom Harvey
13.11	Hoist Availability	In certain exceptionally well organized shafts, utilization factors as high as 92% have been reported, but a more reasonable figure of 70% should be adopted. With multi-purpose (skipping and caging) hoists, the availability will be much lower. Source: Fred Edwards
13.12	Rope Pull	The manufacturer’s certified rope pull rating for a drum hoist assumes the rope flight angle is 25 degrees or more from the horizontal. The rope pull rating should be reduced by 10% for an installation where the ropes run horizontally between the hoist and the head sheave. Source: Ingersoll-Rand
13.13	Hoist Drums	The hoist drum should be designed to coil rope for the hoisting distance plus an allowance equal in length to 10 dead wraps on the drum. Source: John Stephenson
13.14	Hoist Drums	The hoist drum should be designed to coil sufficient rope for the hoisting distance plus an allowance of 500 feet, for most applications. Very deep shafts may need 600 feet of allowance. Source: Jack de la Vergne
13.15	Hoist Drums	The hoist drum should be designed to coil sufficient rope for the hoisting distance plus the statutory three dead wraps, the allowance for rope cuts and drum pull-ins for the life of the ropes plus at least 200 feet of spare rope. (At least 250 feet of spare rope is desirable for deep shafts.) Source: Largo Albert
13.16	Hoist Drums	The depth of rope groove on the drum should be between 0.30 and 0.31 times the rope diameter. Source: South African Bureau of Standards (SABS 0294)
13.17	Hoist Drums	The pitch distance between rope grooves on the drum face (of older European hoists) is the rope diameter plus one-sixteenth of an inch for ropes up to 2½ inches diameter. Source: Henry Broughton
13.18	Hoist Drums	The pitch distance between rope grooves on the drum face on the hoists that we manufactured is the rope diameter plus one-sixteenth of an inch for ropes up to 1¾ inches diameter, then it increases to one-eighth of an inch. Source: Ingersoll Rand
13.19	Hoist Drums	The pitch distance between rope grooves on the drum face of older hoists may be taken at the rope diameter plus 4% for ropes of any diameter, when calculating rope drum capacity of the drum. Source: Larry Cooper
13.20	Hoist Drums	Newly manufactured drum hoists (and replacement drum shells) invariably employ half-pitch crossover parallel grooving for which the pitch distance should exceed the rope diameter by 7%. Source: Largo Albert
13.21	Hoist Drums	The pitch distance on drum winders (hoists) should be between 5.5% and 7% larger than the nominal rope diameter. Source: South African Bureau of Standards (SABS 0294)
13.22	Hoist Drums	The maximum allowable hoop stress for drum shells is 25,000 psi; the maximum allowable bending stress for drum shells is 15,000 psi. Source: Julius Butty
13.23	Hoist Drums	The flanges on hoist drums must project either twice the rope diameter or 2 inches (whichever is greater) beyond the last layer of rope. Source: Construction Safety Association of Ontario
13.24	Hoist Drums	The flanges on hoist drums should project at least 2½ rope diameters beyond the last layer of rope. Source: South African Bureau of Standards (SABS 0294)
13.25	Hoist Drums	The flanges on hoist drums must project a minimum of 30 mm beyond the last layer of rope. Source: Swedish Code of Mining Practice
13.26	Shafts and Gearing	At installation, the allowable out-of-level tolerance for the main shaft of a drum hoist is one thousandth of an inch per foot of length. Source: Gary Wilmott
13.27	Shafts and Gearing	Square keys are recommended for shafts up to 165 mm (6½ inches) diameter. Rectangular keys are recommended for larger shafts. Standard taper on taper keys is 1:100 (1/8 inch per foot). Source: Hamilton’s Gear Book
13.28	Shafts and Gearing	The width of a key should be ¼ the shaft diameter. Source: Jack de la Vergne
13.29	Shafts and Gearing	Drum shafts (or other shafts for frequently reversed motion) should not have any key at all. Hubs, couplings, and the like should instead be shrink fitted to the shaft. Removal by the oil injection method is recommended. Source: Sigurd Grimestad
13.30	Shafts and Gearing	For geared drives, pinion gears should have a minimum number of 12 teeth and preferably not less than 17. If the pinion has less than 17 teeth, undercutting may occur and the teeth should be cut long addendum (“addendum” is the distance between the pitch line and the crown of the tooth). Source: Hamilton’s Gear Book
13.31	Shafts and Gearing	For geared drive drum hoists, pinion gears should have a minimum number of 14 teeth. Source: Ingersoll Rand
13.32	Overwind and Underwind	The overwind distance required for a drum hoist is one foot for every hundred fpm of hoist line speed. Source: Tad Barton
13.33	Overwind and Underwind	The overwind distance required for a drum hoist is 1.6 feet for every hundred fpm (1 m for every 1 m/s) of hoist line speed, to a maximum of 10m. Source: Sigurd Grimestad
13.34	Overwind and Underwind	The overwind distance required for a high-speed drum hoist is 7m. Source: Peter Collins
13.35	Overwind and Underwind	The underwind distance required is normally equal to ½ the overwind distance. Source: Jack de la Vergne
13.36	Hoist Inertia	The residual inertia of a double-drum hoist (including the head sheaves and motor drive, but not ropes and conveyances), reduced to rope centre, is approximately equal to the weight of 10,300m (33,800 feet) of the hoist rope. For example, the approximate inertia (WR²) of a 10-foot double-drum hoist designed for 1½ inch diameter stranded ropes weighing 4 lbs. per foot, will be:
		5 x 5 x 4 x 33,800 = 3,380,000 Lbs-feet².
		Source: Tom Harvey
13.37	Hoist Inertia	The inertia of a single-drum hoist may be assumed to be 2/3 that of a double-drum hoist of the same diameter. Source: Ingersoll-Rand
13.38	Hoist Inertia	The inertia (in lbs-feet²) of the rotor of a direct current (DC) geared drive hoist motor is approximately equal to 1,800 times the horsepower of the motor divided by its speed (RPM) to the power of 1.5:
		WR² = 1,800 [HP/RPM] ^1.5
		Source: Khoa Mai
13.39	Hoist Inertia	The inertia (in lbs-feet²) of the rotor of a DC direct drive hoist motor is approximately equal to 850 times the horsepower of the motor divided by its speed (RPM) to the power of 1.35:
		WR² = 850 [HP/RPM] ^1.35
		Source: Khoa Mai
13.40	Root Mean Square Power	Power consumption (energy portion of utility billing) of a drum hoist is approximately 75% of root mean square (RMS) power equivalent. Source: Unknown
13.41	Root Mean Square Power	In calculating the RMS horsepower requirements of a drum hoist, it is not important to determine a precise value for the inertia. A 10% error in inertia results in a 2% error in the RMS horsepower. Source: Tom Harvey
13.42	Peak Power	For a DC hoist motor, the peak power should not exceed 2.1 times the RMS power for good commutation. Source: Tom Harvey
13.43	Peak Power	For a DC hoist motor, the peak power should not exceed 2.0 times the rated motor power for good commutation. Source: Sigurd Grimestad
13.44	Peak Power	A typical AC induction hoist motor is supplied with a 250% breakdown torque. In application, this means that the peak horsepower should not exceed 1.8 times the RMS power. Source: Larry Gill
13.45	Delivery	The delivery time for a new drum hoist is approximately 1 month per foot of diameter (i.e. for a 12-foot double-drum hoist, the delivery time is approximately 12 months). Source: Dick Roach
13.46	Delivery	The delivery time for new wire ropes for mine hoists is approximately four months for typical requirements. For special ropes manufactured overseas, delivery is near six months. Source: Khoa Mai