13
Correction factors c
6
and c
8
Like the basic service factor c
0
, the factors to be added for pulleys
and idlers c
6
and for start/stop frequency under load c
8
are to be
taken as
approximations
only. These factors are allowances to
be made for unusual operating conditions and are added where
applicable to the basic service factor c
0
.
Table 2.2: Correction factors c
6
and c
8
for special operating
conditions
Type of operating
Designation and
Remarks
conditions
value of
correction factor
Use of
c
6
= 0.2
0.2 per idler
tensioning and
to a maximum of
guide idlers
1.0
Start/stop
c
8
= 0.1 ... 0.3
depending upon
and/or
frequency, up to
reversing
approx. 1.5 times
under load
nominal torque
with low start-up
torque (e.g. star/
delta connection)
c
8
= 0.3 ... 0.5
depending upon
frequency, above
approx. 1.5 times
nominal torque
with high start-up
torque
The correction factor c
6
applies when more than two pulleys are
used. Such use of additional pulleys must be separately checked at
the design stage.
Large drive torque of inertia should be classified as external loads.
2 Basics of Drive Design
2.1 Service factors, additional factors and formulae
Length factor c
3
for ZRM/ZRP belts
The
approximate values
for the length factor c
3
are given in
Table 2.3 and apply only to rotating highly loaded drives fitted
with ZRM/ZRP timing belts.
The length factor c
3
takes into account the increase or decrease of
belt flexing when using a short or long belt.
Note the units used for the individual parts of the formulae. The formulae for the driven torque and driven power also apply for the driver
side using the formula symbols M
An
, P
An
, d
w1
and n
1
in place of M
Ab
, P
Ab
, d
w2
and n
2eff
.
General
For i = 1 or z = z
1
= z
2
Formulae
for explanation of symbols see page 14
v
eff
=
=
i
eff
=
=
=
i =
d
w1
=
d
w2
=
(mm)
M
Ab
=
(Nm)
P
Ab
=
(kW)
M
Ab
=
(Nm)
P
Ab
=
(kW)
M
Ab
=
(Nm)
P
Ab
=
(kW)
M
Ab
· n
2eff
9550
S
n3
· d
w2
· n
2eff
19100 · 1000
S
n3
· v
eff
1000
General
driven torque and driven power
d
w2
· S
n3
2000
9550 · P
Ab
n
2eff
d
w2
· P
Ab
2 · v
eff
d
w1
· n
1
19100
z
1
· t
π
d
w2
· n
2eff
19100
z
2
· t
π
Drive calculation ZRM/ZRP
see page 26
Drive calculation ZRL-M
see page 34
Drive calculation ZRL-V
see page 37
m
s
( )
L
w
= 2 · a
nom
+ z · t
(mm)
a
nom
=
t
(mm)
z
R
=
z
R
– z
2
L
w
t
z
2
z
1
d
w2
d
w1
n
1
n
2eff
n
1
n
2
Table 2.3: Length factor c
3
for ZRM/ZRP belts
Section
Pitch length L
w
Length factor
(mm)
c
3
MXL; T2.5
≤
190
0.8
> 190
≤
260
0.9
> 260
≤
400
1.0
> 400
1.1
XL; T5 (D); AT5
≤
440
0.8
> 440
≤
555
0.9
> 555
≤
800
1.0
> 800
1.1
L; T10 (D); AT10
≤
600
0.8
> 600
≤
920
0.9
> 920
≤
1500
1.0
> 1500
1.1
T20 (D); AT20
≤
1260
0.8
> 1260
≤
1880
0.9
> 1880
≤
3000
1.0
> 3000
1.1
Summary of Contents for ZRL
Page 54: ...53 ...
Page 95: ...94 ZRM ZRP Data Sheet Notes ...