Manitowoc Grove RT770E Operator's Manual page 27

RT770E OPERATOR MANUAL
Simplified Method to Determine Maximum Permissible Wind Speed
V(z) < 13.4 m/s (30 mph)
Main Boom
Allowable load =
Published Rated Capacity
Determine Ap
Ap / Allowable Load < 0.5 m
(Ap / Allowable Load < 0.0025 ft
YES
It is permissible to lift Allowable load
at this windspeed, V(z)
V(z) = 3 second gust wind speed at boom tip, m/s (mph)
Ap = Projected Wind Area of Load, m
Grove
Determine 3-Second Gust
Wind Speed at boom tip,
13.4 m/s < V(z) < 20.1 m/s
(30 mph < V(z) < 45 mph)
Use Main Boom on
Fully Extended Outriggers ONLY
Calculate Allowable Load
Ap = maximum height X maximum length
See Figure 2-2
Determine Cd of Load
NO
2
/t ?
2
/lb)
From Figure 2-3
Awr
(Awr
(Allow)
From (Table 2-3)
2 2
(ft )
Published 04-04-2017, Control # 446-09
V(z)
2
= 1.2 m /t
(Allow)
2
= 0.0059 ft /lb)
YES
YES
Awr = Actual Wind Resistance Area for the Load, m
(load)
Awr = Allowable Wind Resistance Area of the Load, m
(Allow)
Cd = air drag coefficient of load
SAFETY INFORMATION
0.14
V(z) = [(z/10) + 0.4]v [m/s]
0.14
V(z) = [(z/33) + 0.4]v [mph]
V(z) > 20.1 m/s (45 mph)
Lifting is not permitted.
Cease Lifting Operations
Allowable Load = Published Rated Capacity
X Capacity Reduction Factor
(from Load Chart Notes)
Calculate
Awr = Ap X Cd
(load)
Calculate
Awr of allowable load
(Allow)
Awr >Awr
(Allow) (load) ?
NO
Calculate Ratio:
Awr / Awr
(load) (Allow)
Determine Maximum Permissible Wind
Speed
Maximum Permissible
Wind Speed > V(z)?
NO
Lifting is not permitted.
Cease Lifting Operations.
Plan the lift when V(z) < calculated
Maximum Permissible Wind Speed.
2
(ft)
2
(ft2
FIGURE 2-1
2
2-9