AD437153353153en-010301.pdf

I mpr o v e uptime , sa v e energy and pr otec t mot ors e ec tiv ely Sof t starters generate z ero harmonics so you can f orget about lters and scr eened cables Selection Guide > VL T® Soft Star ter

Improve uptime, save energy

and protect motors eectively

Soft starters generate zero harmonics

so you can forget about lters and screened cables

Selection Guide > VLT® Soft Starter

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

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