Ametek Gemco H Series User guide

Brake Systems Application Guide
INDEX
INTRODUCTION
BRAKE SUMMARY AND KEY FEATURES 3
TYPICAL DESCRIPTION AND APPLICATIONS HYDRAULIC BRAKES 4-7
TYPICAL DESCRIPTION AND APPLICATIONS ELECTRIC BRAKES 8
BRAKE CALCULATIONS
SELECTING BRAKE TORQUE BASED ON MOTOR DATA 9
CRANE HOIST BRAKING TORQUE 9
CRANE TROLLEY BRAKING TORQUE 10
SELECTING BRAKE SIZE BASED ON LOAD DATA 10
OVERHAULING LOAD TORQUE 12
BRAKE THERMAL CAPACITY 13
OVERHAULING LOADS 14
HYDRAULIC BRAKE SELECTION FOR BRIDGE BRAKES 15
HYDRAULIC BRAKE TORQUE RATINGS AND THERMAL CAPACITIES 16
DC MAGNETIC SHOE BRAKE TORQUE RATINGS AND THERMAL CAPACITIES 20
NOTE: Pages 9 through 14 describe brake calculations that in general apply to all style
Gemco brakes. The hydraulic brake selection, pages 15 through 19 are specifically for
hydraulic brakes used as bridge brakes for overhead cranes.
2

Brake Systems Application Guide
BRAKE SUMMARY AND KEY FEATURES
HYDRAULIC, MAGNETIC, AND
ELECTRO-THRUST BRAKE SYSTEMS
Gemco Industrial Brakes stop virtually any type of industrial machine. Applications such as indoor
and outdoor bridge cranes, gantries, heavy-duty cranes, high duty cycle cranes, lock and dam
projects, stacker reclaimers, commercial laundry equipment, and heavy-duty industrial transfer
equipment are just some of the uses for Gemco Industrial Brakes.
These field-proven, high performance brake systems are tough and reliable, and they provide
extended, trouble-free service. That’s because they are designed and built to exacting specifi-
cations by Gemco. For more than 40 years, Gemco has been an acknowledged leader in brake
systems technology for heavy-duty industrial applications.
BRAKE SYSTEM KEY FEATURES SUMMARY
HHM AH AHM CB TM ET S DB
Hydraulically Applied • • • •
Spring Applied • • • • •
Controlled Stopping • • • •
Parking • • • • • • •
AISE Rated • • •
H-Manual Hydraulic Applied Brake System
HM -Manual Hydraulic Brake with Parking
AH -Air-Over-Hydraulic Brake System, for remote control
AHM -Air-Over-Hydraulic Brake with Parking
CB -AC Brake, Spring Set
TM - DC Brake, Spring Set (Auxiliary Hydraulic Cyl. available)
ET -Electro-Thrust, Spring Set Release by Electro-Hydraulic Actuator
(Auxiliary Hydraulic Cylinder Available)
DB -Electro-Thrust, Spring Set Release by Electro-Hydraulic Actuator
(Auxiliary Hydraulic Cylinder Available)
Note: Custom design and special brake assemblies are available; please consult factory
for application assistance. 3

Brake Systems Application Guide
TYPICAL DESCRIPTION AND APPLICATIONS
HYDRAULIC BRAKES
DESCRIPTION:
Type H manually operated hydraulic brakes for
smooth controlled service stops. Sizes are 6” through
18” with torque ratings 150 to 900 ft-lbs.; one and two
brake systems.
TYPICAL APPLICATIONS:
Bridge brakes for overhead, gantries and heavy duty
cranes. The hydraulic brakes described in the
following pages have been utilized for many years in
steel mill cranes, shipyards and other applications
where an “operator” control stop is desirable.
DESCRIPTION:
Type HM brakes not only provide smooth controlled
stopping but are also equipped with a spring applied
parking actuator. Sizes for single brake systems 6”
through 18”, two brake systems 6” and 8”.
TYPICAL APPLICATIONS:
Bridge brakes for “outdoor” cranes that require
parking feature due to wind loads.
4

Brake Systems Application Guide
DESCRIPTION:
Type AH-ARC (Air/Hydraulic Air
Remote Control) brake system for
stopping large loads. Sizes one, two
and four brake systems - 6” through
18”.
TYPICAL APPLICATIONS:
Large overhead crane brakes for
ladle cranes and other hot metal
cranes, usually four brakes systems.
DESCRIPTION:
Type AH-H RC (Air/Hydraulic-
Hydraulic Remote Control) brake
systems with operator hydraulic
control. Sizes one, two and four
brake systems - 6” through 18”.
TYPICAL APPLICATIONS:
Bridge brakes for overhead crane
with moving trolley cabs that require
more than 60 feet travel.
5

Brake Systems Application Guide
DESCRIPTION:
Type AH-ERC systems for
operating hydraulic brakes by
radio or pendent control. Size
one, two and four brake systems
- 6” through 8” brake.
TYPICAL APPLICATIONS:
Any remote radio or pendent
control brake requirement for
bridge brakes.
DESCRIPTION:
Type AH-ERC Conversion
package adds remote control
capability to existing H brake
systems. Size one and two brake
systems.
TYPICAL APPLICATIONS:
Field modification for remote
control capabilities on existing
manual system.
6

Brake Systems Application Guide
DESCRIPTION:
Type AHM System. All three of
the previously described air over
hydraulic systems can be
provided with parking. (AHM-
ARC, AHM-HRC, and AHM-
ERC).
TYPICAL APPLICATIONS:
As previously described but with
parking for “outdoor crane”
applications.
DESCRIPTION:
Type TMH System for remote
operation of D.C. Electric Brake
assemblies. Auxiliary cab control
also allows hydraulic operation for
controlled braking. sizes are 4’ to
23”, one and two brake systems.
TYPICAL APPLICATIONS:
Bridge brakes for overhead cranes.
Since electric brake is spring set,
parking feature is also present.
Note: Auxiliary cab control is also
available for EH style electro-thrust
brakes.
7

Brake Systems Application Guide
DESCRIPTION:
Type CB brakes spring applied electrically
released via solenoid. Sizes, 4 ½ to 10’, general
duty.
TYPICAL APPLICATIONS:
Light duty crane bridge brakes and holding
brakes.
DESCRIPTION:
Type TM brakes spring applied electrically
released via D.C. magnet coils. AISE sizes, Mill
Duty.
TYPICAL APPLICATIONS:
Crane hoist, stationary hoist, drive roller
brakes, and lock and dam motor brakes.
DESCRIPTION:
Type ET brake spring applied electrical release
by A.C. or D.C. electro-thrust mechanism.
TYPICAL APPLICATIONS:
Bridge brakes, lock and dam project,
stacker reclaimers, container cranes.
Note: Auxiliary hydraulic cylinder is also available
for manual cab control.
DESCRIPTION:
Type DB brake spring applied electrical release
by A.C. or D.C. electro-thrust mechanism.
TYPICAL APPLICATIONS:
Bridge brakes, lock and dam project, stacker
reclaimers, container cranes.
Note: Auxiliary hydraulic cylinder is also available
for manual cab control.
8

Brake Systems Application Guide
INTRODUCTION
When selecting the proper brake for a specific application, there are several factors to consider; a
few that need to be reviewed are brake torque, stopping time and/or deceleration rates, brake
mounting, brake location, thermal rating, environment, and brake style.
The brake systems manufactured by Gemco Industrial Brake Products are external friction
brakes. Applications for which these brakes are suited can be classified into two general
categories: non-overhauling and overhauling.
A) Non-overhauling loads are typically horizontally moving masses such as crane
bridges, crane trolleys, and horizontal conveyors.
B) Overhauling loads tend to “run up” in speed if a brake is not present, examples of
which are crane hoists, winches, lifts, and downhill conveyors.
Type A (non-overhauling) loads require brake torque only to stop the load and will remain at rest
due to friction. Type B (overhauling) loads have two torque requirements; the first is braking
torque required to stop the load, and the second is the torque required to hold the load at rest.
SELECTING BRAKE TORQUE BASED ON MOTOR DATA
The full -load torque of a motor is a function of horsepower and speed and is commonly used to
determine a brake torque rating. The brake torque rating is to equal or exceed the full load torque
of a motor. The formula to calculate the full load motor torque is as follows:
5250 x HP x S.F.
T = RPM
where: 5250 =constant
HP =motor horsepower
RPM =speed of motor shaft
S.F. =application service factor
T=static brake torque
CRANE HOIST BRAKING TORQUE
Sizing of crane hoist brakes is typically based upon full load hoisting torque. The following is a
brief summary of guidelines for hoist brakes.
Each hoist on a crane should be equipped with at least one spring-set magnetic brake; hoists
handling hot metal should be equipped with more than one brake. Brake rating expressed as a
percent of hoisting torque at the point of brake application should be no less than the following:
1) 150% when only one brake is used.
2) 150% when multiple brakes are used and the hoist is not used to handle hot metal.
Failure of any one brake shall not reduce braking torque below 100%.
3) 175% for hoists handling hot metal. Failure of any one brake shall not reduce brake
torque below 125%.9

Brake Systems Application Guide
CRANE TROLLEY BRAKING TORQUE
Crane trolley brakes are typically sized with a torque rating less than the motor’s full load torque
(service factor less than 1.0) to provide a longer stopping time or a “soft stop.” Overhead crane
trolley brakes are minimized to prevent sway of the hook and load. Typical service factor is 50%
for “soft stopping.”
SELECTING BRAKE SIZE BASED ON LOAD DATA
For applications where high inertial loads exist or where a specific stopping time or distance is
required, the brake should be selected based on the total inertia of the load. Total system inertia
reflected to the brake shaft can be expressed as follows:
WKT2=WKB2 + WKM2 + WKL2
where: WKT2=Total reflected inertia to brake (Ib-ft2)
WKB2=Inertia of brake wheel (Ib-ft2)
WKM2=Inertia of motor rotor (Ib-ft2)
WKL2=Equivalent inertia of load reflected to
shaft (lb-ft2) brake
The following formulas apply when calculating inertia of systems with different rotational speeds
or linear moving loads to brake shaft speeds.
Rotary Motion:
WKb2=WKL2(NL / NB)2
where: WKb2=Inertia of rotation load reflected to brake shaft
(lb-ft2)
WKL2=Inertia of rotating load (lb-ft2)
NL=Shaft speed at load (RPM)
NB=Shaft speed at brake (RPM)
10

Brake Systems Application Guide
Horizontal Linear Motion:
WKW2=W (V / 2pNB)2
where: WKW2=Equivalent inertia of moving load
reflected to brake shaft (lb-ft2)
W=Weight of linear load (Ib)
V=Linear velocity of load (ft/mm)
NB=Shaft speed at brake (RPM)
With the total system inertia calculated, the required average dynamic torque for a desired
stopping time can be calculated using the following formula:
WK
T
2
x NB
Td=308 x t
where: Td=Average dynamic braking torque (lb-ft)
WKT2=Total inertia reflected to brake (lb-ft2)
NB=Shaft speed at brake (RPM)
t=Desired stopping time (sec.)
308 =Constant
To determine stopping time for a given brake torque this formula can be rewritten as follows:
WKT2* NB
t=308 x Td
For some brake styles the time required until the brake lining makes contact with the wheel may
be significant. Time required to stop is then as follows:
WK
T
2
xN
B
t=t1 +308 x Td
where: t1=Time between signal and moment when brake
torque is actually applied (sec.)
11

Brake Systems Application Guide
For linear applications, the dynamic braking torque can be calculated directly using the following
formula: W x V x r
Td=g x t
where: Td=Average dynamic braking torque (lb-ft)
W=Total weight of linear moving load (lb.)
V=Linear velocity of load (ft/sec.)
g=Gravitational acceleration constant (32.2 ft/sec2)
t=Desired stopping time (sec.)
r=Length of movement arm or wheel radius (ft.)
This formula is applicable on crane trolley or crane bridge brakes.
OVERHAULING LOAD TORQUE
Applications with a descending load, such as crane hoists, elevators, etc., require a brake with
sufficient torque both to stop the load and to hold it at rest. The total system inertia reflected to
the brake shaft speed should be calculated using the previous formulas. Next, the average
dynamic torque should be calculated with the previous formula:
WKT2* NB
Td=308 * t
Next, the overhauling torque reflected to the brake shaft can be determined by the following
formula: 0.159 * W * V
To=NB
where: To=Overhauling dynamic torque of load reflected to brake
shaft (lb-ft)
W=Weight of overhauling load (lb.)
V=Linear velocity of descending load (ft/min.)
NB=Shaft speed at brake (RPM)
0.159 =Constant (1/2 p)
12

Brake Systems Application Guide
The total dynamic torque required for an overhauling load is the sum of Tdand T0, as follows:
Tt=Td+ To
where: Tt=Total dynamic torque for descending load
BRAKE THERMAL CAPACITY
When a brake stops a load, the energy required to stop is converted to heat. This heat is
absorbed by the brake and the wheel. The ability to absorb and dissipate heat without exceeding
temperature limitations is known as thermal capacity.
There are two types of thermal capacity. The first is referred to as the maximum energy the brake
can absorb in one stop, or emergency stop. The second is the heat dissipation capability of the
brake if it is for frequent stopping.
The kinetic energy that must be absorbed and dissipated by the brake can be determined as
follows:
Rotational Loads:
WKT2 X NB2
KEr=5875
where: KEr=Kinetic energy of rotating load (ft-lb)
WK
T
2=Inertia of the rotating load reflected to brake shaft (Ib-ft2)
NB=Shaft speed at brake (RPM)
5875 =Constant
W x V2
KEL=2g
where: KEL=Kinetic energy (ft-lb)
W=Weight of load (lb.)
V=Linear velocity of load, (ft/sec.)
g=Gravitational constant (32.2 ft/sec2)13

Brake Systems Application Guide
OVERHAULING LOADS
In the case of overhauling loads, both the kinetic energy of the linear and rotating loads and the
potential energy transformed into kinetic energy by the change in height must be considered. The
potential energy transformed to kinetic energy is determined as follows:
PE =WS
Where: PE =Change in potential energy, (ft-Ib)
W=Weight of overhauling load (Ib)
S=Distance load travels (ft.)
Therefore, the total energy to be absorbed by the brake in stopping an overhauling load is:
ET =KEL + KEr + PE
In general, a brake will repetitively stop a load at the duty cycle that the electric motor can
repetitively start the load.
For rotating or linear loads, the rate at which a brake is required to absorb and dissipate heat
when frequently cycled is determined as follows:
WKT2 x NB2 x NO
TC=3,220,000
TC =Thermal capacity (HP - sec/min)
WKT2=Total system inertia (Ib-ft2)
NB=Shaft speed at brake (RPM)
where:
N0=Number of stops per minute
3,220,000 = Constant
For overhauling loads the rate at which the brake is required to absorb and dissipate heat when
frequently cycled is determined as follows:
TC =E
T
x N
O
550
where: TC =Thermal capacity (HP-sec/min)
ET=Total energy brake absorbs (ft-Ibs)
550 =Constant
N0=Number of stops per minute 14

Brake Systems Application Guide
BRAKE SELECTION FOR BRIDGE BRAKES
The following formulas apply for calculating linear loads such as bridge brake applications:
W x V2W x V x r
KE
L
=2 x g T
d
=g x t
where: KEL=Kinetic energy (ft-lb)
W=Weight (lb.)
V=Linear velocity (ft/sec)
G=Gravitational constant (32.2 ft/sec2)
R=Wheel radius (ft)
T=Stopping time
Td=Average dynamic torque (lb-ft)
Given in terms of tons, wheel diameter, gear ratios, etc., the specifications necessary to
calculate crane bridge brakes include the following:
Empty crane weight — WE _____Tons
Full load crane weight — WL _____Tons
Max. bridge speed — FPM _____Ft/Min.
Stops per hour — N_____Number value
Track wheel diameter — DIA _____Inches
*Gear ratio brake shaft to track wheel — R_____(To 1)
Number of brakes — NB _____Number value
Acceleration rate — A_____Ft/Sec2.
Min. deceleration rate — dMN _____Ft/Sec2.
Max. deceleration rate — dMX _____Ft/Sec2.
Drive motor inertia — WKM2_____(Lb-Ft2)
* Drive motor RPM can be used to verify gear ratios, etc., for a maximum speed and track
diameter.
In general, service bridge brakes should have sufficient thermal and torque range to stop
the bridge within a distance of 10% of the full load speed with full load, or at a deceleration
rate as specified by the original manufacturer.
15

Brake Systems Application Guide
The kinetic energy and torque calculations can be stated in terms of crane specifications as
follows:
Kinetic energy absorption rate, per brake per hour:
N x (FPM)
2
x (WE + WL)
KE =232 x NB
Minimum stopping torque (to stop empty crane at minimum deceleration rate):
2.59 x WE x dMN x DIA
TMN =NB x R
Maximum stopping torque (to stop fully loaded crane at maximum deceleration rate):
2.59 x WL x dMX x DIA
TMX =NB x R
HYDRAULIC BRAKE TORQUE RATINGS AND THERMAL CAPACITIES
Using the table below, select the smallest brake size that will exceed KE and TMX calculations
listed above. TMN calculations for air powered systems should be above “Minimum” torque
limits below:
Max. Dynamic Torque per Brake (Ib-ft.)**
Brake
Size Max. KE per Brake per Hour
(ft.-Ib) Type H 1-
Brake Type H 2-Brake or Type HM All Air Powered
Min. Dynamic Torque, All Air
Powered Systems (lb-ft.)
6 x 3 1.0 x 106150 150 350 25
8 x 3 1.25 x 106200 200 450 50
10 x 4 2.5 x 10 425 250 1000 75
14 x 6 5.0 x 106600 350 1400 125
18 x 8 9.0 x 106900 550 1800 175
**Based on 70 lb. pedal force, 8” max. pedal travel on Type H or HM manual systems.
16

Brake Systems Application Guide
Maximum stops per hour can be calculated using the following:
N x (Max. KE per brake per hour)
Max. stops/hr. =KE
where: (Max. KE per brake per hour) = Value for brake size as shown in table above.
The additional torque required to stop the drive rotor and the brake wheel inertia is normally
insignificant and is ignored when the gear ratio (R) is less than about 10 x 1. If the gear ratio, and
thus the drive rotor inertia is abnormally high, considerable torque may be needed just to stop the
drive rotor.
To calculate the additional torque needed to stop the drive rotor and brake wheel inertia, proceed
as follows:
1. Complete the previous calculations to establish the prelimary brake size.
BRAKE SIZE BRAKE WHEEL INERTIA
6x 3 .55 lb-Ft2.
8x 3 1.41 Lb-Ft2.
10 x 4 4.25 Lb-Ft2.
14 x 6 24.20 Lb-Ft2.
18 x 8 75.73 Lb-Ft2.
2. Record the following data from brake wheel inertia table above and additional data from
previous calculations.
WK2Brake wheel Inertia _________________ Lb-Ft2.
WK2Drive Rotor Inertia + Lb-Ft2.
WK2 Total (Drive Motor and Wheel) _________________ Lb-Ft2.
R, Gear Ratio _________________ x1
dMN Deceleration Rate _________________ ft/sec2.
dMX Deceleration Rate @ Full Load _________________ ft/sec2.
DIA, Track Wheel _________________ inches
3. Calculate No Load Drive Torque, TNLD:
WK2Total x Rx dMN = ________ x ________ x ________
1.34 x DIA. _____________________________ = ________Lb-Ft.
1.34 x _______
4. Calculate Full Load Drive Torque, TFLD:
TNLD X dMX = ________ x ________ = ________ Lb-Ft.
dMN ________
17

Brake Systems Application Guide
5.Calculate Total Minimum and Maximum Torques:
TMN (previous) ___________Lb-Ft. TMX (previous) ___________Lb-Ft.
TNLD + ___________ Lb-Ft. TFLD + Lb-Ft.
TMNT ___________ Lb-Ft. TMxT Lb-Ft.
6.Check to determine that TMxT is still within the torque limits of the brake size selected. If
necessary, recalculate the problem based on alternate brake size and brakewheel inertia.
The chart below shows the dynamic torque values developed by manually operated brake
systems. Maximum torques tabulated are developed at 70 lb. pedal force, the limit indicated by
AISE and OSHA. Two maximum values are shown for 10 x 4, 14 x 6, and 18 x 8 brakes, as
follows:
The chart below shows the dynamic torque ranges developed by air powered hydraulic
systems.
The maximum torques shown are developed by a 70 lb. force applied on the air treadle on
Type A/H systems or applied on the pedal of the control cylinder on Type NHM-HRC systems.
Air powered hydraulic systems include either a 1 x 5 or a 1 x 8 air hydraulic pressure cluster to
apply the service brake. In addition, 10”, 14”, and 18” brakes include either a 7/8” diameter or a
1-1/8” diameter service brake actuator. Hence, 6” and 8” brakes have two possible maximum
torque limits, while 10”, 14”, and 18” have four possible maximum torque limits.
The minimum torque limits shown are developed by light application of the treadle or pedal.
Because of hysteresis and friction in the power system valves, it is not practical to consistently
control less torque than the minimum calculated.
18

Brake Systems Application Guide
Static holding torque values tabulated below are those developed by the parking spring on the
Type HM brakes. The brake must be correctly adjusted in order to get the holding torque
tabulated.
Brake Size 6 x 3 8 x 3 10 x 4 14 x 6 18 x 8
Holding Torque, lb-ft. 35 50 450 550 700
19

Brake Systems Application Guide
TM, ET and DB SHOE BRAKE TORQUE RATINGS AND THERMAL CAPACITIES
Maximum Torque in Lbs.-Ft (Max.)
Series Brake Shunt Brake
1/2 HR 1 HR 1 HR 8 HR
TM 43
TM 63
TM 83
TM 1035
TM 1355
TM 1655
TM 1985
TM 2311
TM 3014
25
50
100
200
550
1000
2000
4000
9000
15
40
65
130
365
650
1300
2600
6000
25
50
100
200
550
1000
2000
4000
9000
15
40
75
150
400
750
1500
3000
6750
BRAKE
STYLE WHEEL DIAMETER
(inches)
TORQUE
LB.FT.
(Max.)
ET8 8100
ET10 10 200
ET13 13 550
ET16 16 1000
ET19 19 2000
ET23 23 4000
ET30 30 9000
Wheel
Size Ft.-Lb. per Hour
4.5”396,000
6.0”660,000
8.0”990,000
10”1,716,000
13”3,300,000
16”5,016,000
19”7,425,000
23”10,890,000
30”18,150,000
BRAKE
STYLE DISC
DIAMETER
(Inches)
TORQUE
LB.FT.
(Max.)
DB12 12 100
DB14 14 200
DB17 17 550
Allowable Heat Absorption for Brake Wheels
DB Torque Ratings
TM Torque Ratings
ET Torque Ratings
AMETEK
®
PATRIOT SENSORS
6380 BROCKWAY ROAD • PECK, MI 48466-9766 USA
800-325-8074 • 810-378-5511 • Fax [phone]
www.patriotsensors.com • www.ametek.com