8.5 Installing Peripheral Devices
■ Installing a Residual Current Device (RCD) or a Residual Current Monitoring Device (RCM)
Residual currents occurring in drive installations can contain AC, DC, and high frequency components that may prevent
a normal RCD/RCM from operating as desired. If an RCD/RCM is required in the installation, always use an all-current-
sensitive device (Type B according to IEC 60755) to ensure proper ground fault interruption.
Leakage currents generated by the drive during normal operation may trip an RCD or RCM even if a ground fault is not
present.
Factors that influence the leakage current are:
• Size of the AC drive
• AC drive carrier frequency
• Motor cable type and length
• EMI/RFI filter
If the RCD/RCM trips spuriously consider changing these items or use an RCD/RCM with a higher trip level.
Choose a RCD/RCM designed specifically for an AC drive. The operation time should be at least 0.1 s with sensitivity
amperage of at least 200 mA per drive. The output waveform o f the drive may cause an increase in leakage current. This
may in turn cause the leakage breaker to malfunction. Increase the sensitivity amperage or lower the carrier frequency to
correct the problem.
• Installing a Magnetic Contactor at the Power Supply Side
Install a magnetic contactor (MC) to the drive input for the purposes explained below.
■ Disconnecting from the Power Supply
Shut off the drive with an MC when a fault occurs in any external equipment such as braking resistors.
N O TIC E:
D o n o t c o n n e c t e le c tro m a g n e tic s w itc h e s o r M C s to the o u tp u t m o to r c irc u its w ith o u t p ro p e r seq ue ncin g. Im p ro p e r
s e q u e n c in g o f o u tp u t m o to r circu its c o u ld re s u lt in d a m a g e to th e drive.
N O TICE:
In s ta ll an M C on the in p u t sid e o f the d riv e w h en the drive s h o u ld n o t a u to m a tic a lly re s ta rt a fte r p o w e r loss. To g e t the full
pe rfo rm a n c e life o u t o f the e le c tro ly tic c a p a cito rs a n d c irc u it relays, re fra in from s w itc h in g th e drive p o w e r s u p p ly o ff a n d on m o re than
on ce e v e ry 3 0 m inutes. F re q u e n t use can d a m a g e the drive. U se the drive to stop a n d sta rt the m otor.
N OTICE:
U se a m a g n e tic c o n ta c to r (M C ) to e n sure th a t p o w e r to the d riv e can b e c o m p le te ly s h u t o ff w h en necessary. The M C s h o u ld
be w ire d so th a t it op en s w h en a fa u lt o u tp u t te rm in a l is triggered.
Note: 1.
Install an M C to the drive input side to prevent the drive from restarting automatically w hen power is restored after momentary
power loss.
2. Set up a delay that prevents the MC from opening prem aturely to continue operating the drive through a mom entary power loss.
■ Protecting the Braking Resistor or Braking Resistor Unit
Use an MC on the input side o f the drive to protect a braking resistor or braking resistor unit from overheat or fire.
W ARNING!
F ire H azard. A p p lic a tio n s u s in g a b ra k in g op tio n s h o u ld w ire a th e rm a l re la y so th a t the o u tp u t c o n ta c to r o p en s w h en the
th e rm a l re la y trips. In a d e q u a te b ra k in g c irc u it p ro te c tio n c o u ld re s u lt in de a th o r s e rio u s in ju ry b y fire from o v e rh e a tin g resisto rs.
W ARNING!
F ire H azard. C onfirm an a c tu a l m o to r o v e rlo a d c o n d itio n is n o t p re s e n t p rio r to in c re a s in g the th e rm a l oL trip de te ctio n
settin g. C h e c k lo c a l e le c tric a l co d e s b e fo re m a k in g a d ju s tm e n ts to m o to r th e rm a l o v e rlo a d settings. F a ilu re to c o m p ly can re s u lt in
de ath o r s e rio u s in ju ry b y fire.
YASKAWA ELECTRIC SIEP C710616 33D YASKAWA AC Drive L1000A Technical Manual
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