3–43

L2002 Inverter

In most applications a controlled deceleration is desirable, corresponding to B091=00. However, applications such as HVAC fan control will often use a free-run stop (B091=01). This practice decreases dynamic stress on system components, prolonging system life. In this case, you will typically set B088=01 in order to resume from the current speed after a free-run stop (see diagram below, right). Note that using the default setting, B088=00, can cause trip events when the inverter attempts to force the load quickly to zero speed.

NOTE: Other events can cause (or be configured to cause) a free-run stop, such as power loss (see “Automatic Restart Mode” on page 3–33), or an intelligent input terminal [FRS] signal. If all free-run stop behavior is important to your application (such as HVAC), be sure to configure each event accordingly.

An additional parameter further configures all instances of a free-run stop. Parameter B003, Retry Wait Time Before Motor Restart, sets the minimum time the inverter will free-run. For example, if B003 = 4 seconds (and B091=01) and the cause of the free-run- stop lasts 10 seconds, the inverter will free-run (coast) for a total of 14 seconds before driving the motor again.

 

 

B091 = 01

Stop Mode = free-run stop

B091 = 01

Stop Mode = free-run stop

 

 

 

 

Resume from 0Hz

 

 

 

Resume from current speed

 

 

B088 = 00

B088 = 01

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Zero-frequency start

 

 

 

 

 

 

 

 

 

 

 

 

 

B003

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Motor

 

 

 

 

 

 

 

 

 

 

Motor

 

 

 

 

 

 

 

 

 

 

 

Wait time

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

speed

 

 

 

 

 

 

 

 

 

 

speed

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[FW, RV]

 

 

 

 

 

 

 

 

 

 

[FW, RV]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

t

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

t

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

“B” Function

 

 

Run

 

 

 

 

Defaults

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Mode

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Func.

 

Name /

 

 

 

 

 

 

 

 

 

–FE(F)

 

–FU

 

 

 

 

 

 

 

 

Description

 

 

Edit

 

 

Units

 

Code

 

SRW Display

 

 

 

 

 

Lo Hi

 

(EU)

 

(USA)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

B088

Restart mode after FRS

Selects how the inverter

 

✘ ✔

 

00

 

 

00

 

 

 

 

 

 

 

 

 

 

 

resumes operation when the

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RUN FRS

 

ZST

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

free-run stop (FRS) is

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

cancelled, two options:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

00 .. Restart from 0Hz

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

01 .. Restart from frequency

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

detected from real speed of

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

motor (frequency matching)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameters Drive

Configuring