AD437153353153en-010301.pdf - 第3页
0 200,00 400,00 600,00 800,00 1000,00 1200,00 Savings in € 70% running 30% ramping 80% running 20% ramping 95% running 5% ramping No bypass External bypass Integrated bypass, MCD 600 I nteg rated b ypass – f or all-round…
Need more uptime and less
maintenance? Then install a soft starter
on your direct-on-line (DOL) or start-
delta installation.
Payback is fast and you get these
additional benefits:
• Lower inrush current reduces
mechanical stress – and minimizes
penalty from the utility company
• Extended system lifetime due to
reduced wear on
– Motor
– Power cables
– Electrical distribution system
• Reduced water hammer in pump
applications. For more application
benefits, see pages 4 and 5.
• After start-up, you can bypass the soft
starter, switching over to run direct-
on-line.
More protection, less space
Select a Danfoss soft starter to win
unique benefits:
• Care for your motor and soft
starter – get good motor and soft
starter protection value, with more
protection features in the soft starter.
• Save panel space with a very
compact footprint
•
Integrate the soft starter with
VLT® drives
•
Programme the soft starter via your
PC using the VLT® Motion Control Tool
MCT 10 set-up software
• Save energy and space with the
integrated bypass
• Ratings up to 1250 A
Why use a soft starter
for speed control?
Forget harmonics
AC drives, also known as variable
speed drives (VSD) work by changing
the frequency input to the motor –
and this causes harmonics on the
supply network. Harmonics do not
affect the AC drive itself. However, if
not kept under control, harmonics can
reduce performance and reliability of
other equipment connected to the
grid, such as generators and circuit
breakers. The solution is to install filters
and screened cables but even then
the harmonic effect is not completely
removed.
Therefore it’s reassuring to know that
a soft starter already fulfils all emission
and immunity requirements laid out
by the EMC directive. The soft starter
does not change the frequency and
therefore does not generate harmful
harmonics. So when using a soft
starter there is no need to consider
harmonics at all.
Reduce torque and current
Using a soft starter you can adjust
torque to the exact level required,
whether or not the application is
loaded. By reducing the starting
torque, mechanical stress on
equipment is alleviated, saving on
service and maintenance costs.
The soft starter also reduces starting
current which means you can avoid
voltage drops in the network.
Save cost
Soft starters cost up to one-tenth the
price of high-power drives. So if your
control requirements are covered by
limiting current only at start and stop,
with no need for constant acceleration
and torque control, then there are
significant savings to be won.
Save space
Soft starters are smaller than AC drives
and the difference becomes more
significant the higher the amp rating
gets. You can save on panel space.
The Danfoss portfolio of soft starters
comprises:
• Eltwin SMC Soft Starter
•
VLT® Compact Starter MCD 201
• VLT® Compact Starter MCD 202
• VLT® Soft Starter MCD 600
For product details, refer to pages 7-15.
When to use a soft starter
AD437153353153en-010301 > VLT® Soft Starter 2
0 200,00 400,00 600,00 800,00 1000,00 1200,00
Savings
in €
70% running
30% ramping
80% running
20% ramping
95% running
5% ramping
No
bypass
External
bypass
Integrated
bypass,
MCD 600
Integrated bypass – for all-round savings
Many Danfoss soft starters provide an
integrated bypass to allow direct-on-
line operation as an alternative. The
integrated bypass offers multiple cost-
saving benefits.
Reduce heat loss
Integrated bypass provides the
opportunity to switch over to direct-
on-line operation, after initial start-up
via the soft starter. By running partially
direct-on-line, you win the advantages
of reduced losses and need for heat
dissipation, thus saving energy due to
decreased cooling requirements.
Save space
Danfoss soft starters with integrated
bypass take up less panel space than a
soft starter with an external contactor.
Save time
With only six terminals instead of
twelve, it is much faster to wire a VLT®
Soft Starter with integrated bypass,
than an alternative soft starter with
external contactor. Less cable is
required, which additionally reduces
cost. Save even more time, by using
the handy set-up software tool
VLT® Motion Control Tool MCT 10 to
configure the soft starter via PC.
You can use the same set-up tool with
VLT® drives.
Save energy – fast payback
The soft starter with integrated bypass
contactor saves space by comparison
to an external contactor connected to
a non-bypassed unit.
Select a soft starter with integrated
bypass when you want to save costs.
The payback time is just months, using
a Danfoss soft starter with integrated
bypass. See how in this example:
Example: VLT® Soft Starter MCD 600
In the example, a VLT® Soft Starter MCD 600 regulates a water pump,
with motor specifications as follows:
Motor
Supply ....................................................................................400 V AC
Rating .....................................................................................132 kW
FLC ...........................................................................................244 A
Start duty .............................................................................300% for 30 seconds
Electricity prices...............................................................(industry – EU)
Estimated savings, non-bypassed versus bypassed
Save more with bypass, compared to no bypass.
The energy saved depends on the relationship between ramping and running.
The more the application is running the more the bypass will save – see illustration.
Cost saving using a bypass, showing the beneficial savings effect
of increased running time and reduced ramping time.
Integrated bypass versus external bypass
Win back your investment faster with integrated bypass, compared to external
bypass. The payback period is only a few months.
Investment
(indexed values)
No bypass,
Direct-on-line
Soft starter with
external bypass
Soft starter with
integrated bypass
VLT® Soft Starter MCD 600
Soft starter 100 100 100
Bypass contactor + wiring
+ mounting
0 58 58
Extra panel space, parts,
and labour
0 3 3
Total 100 161 161
Extra cost compared
to no bypass
- 61 61
Simple payback period
[months]
– 3.3 3.3
AD437153353153en-010301 > VLT® Soft Starter
3
Centrifugal pump
– Water
Need to reduce water pressure surges
and mains supply disturbance at start-
up? Then a gentle start
using a soft starter is a good idea.
It also provides a soft stop to control
the effects of fluid hammer often
associated with uncontrolled pump
stop – ultimately extending pump
life and reducing running costs. For
new projects, build these savings in
at design phase – there is no need
to specify pressure surge tanks and
motorized valves to cater for repetitive
high-pressure surges. The minimum
start current function reduces
electrical disturbance on mains supply
and limits demand on supply as well –
reducing reticulation costs for
example in farmland irrigation projects.
The soft starter
• Prevents motor overheating via
integrated protection
• Ensures that pump does not run in
reverse, via start-up protection
• Detects blocked pipes or lack of
fluid via undercurrent protection,
thus preventing unnecessary pump
damage
Centrifugal fan
– HVAC
Extend the life of centrifugal fans
by adding a soft starter – to ensure
gentle acceleration and deceleration,
minimizing wear on coupling, belts,
and bearings.
The soft starter
• Reduces electrical disturbance on the
supply via a minimal start current
• Prevents overheating of motor
windings and body
• Prevents starting when fan direction
is reversed, avoiding damage
• Trips in the event of excess start time,
indicating a jammed or stalled fan,
also providing early indication of
bearing failure
• Detects broken couplings and belts
or clogged fan filter, via and optional
trip or flag for motor undercurrent
To integrate the soft starter directly
with a BMS, the VLT® Soft Starter MCD
600 supports monitoring fan loading,
without the need for extra equipment
an analog output.
Compressor
– Protect your motor
Has the compressor ever locked up,
for instance due to entry of liquid
ammonia? Using a soft starter,
ongoing monitoring prevents damage
to motor, compressor, and couplings in
a lock up situation.
Soft starters provide instant protection
against motor overload, by tripping
the motor immediately.
The soft starter
• Enables load shedding before the soft
starter trips, for compressor overload
or motor overtemperature
• Trips to prevent motor damage
when start-up time exceeds a pre-
programmed limit, for example due
to a jammed or stalled compressor
• Monitors the compressor load using a
0-20 mA/4-20 mA analog output
• Enables optimized compressor
performance with dual speed
dahlander motor control
• Avoids short cycling via restart delay,
promoting longer life of motor,
compressor, and coupling
• Is an easy retrofit for start/delta
starters
Applications
AD437153353153en-010301 > VLT® Soft Starter 4