Spellman ST SERIES Instruction Manual Download

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ST/STR/STA MANUAL

118107-001 REV J

functionality.  HIGH  VOLTAGE  OFF  and  HIGH
VOLTAGE  ON  are  controlled  by  momentary  normally
closed, normally open contacts, respectively between pins
14  and  15,  and  pins  15  and  16.    See  Figure  3.4  for
recommended interface.

EXTERNAL INHIBIT:

The External inhibit allows the

user to inhibit the power supply output without putting the
power  supply  into  the  HIGH  VOLTAGE  OFF  mode.
This  circuit  can  be  used  to  generate  fast  slewing  output
waveforms or control high voltage generation as in Laser
and  Capacitor  discharge  applications.  The  maximum
inhibit  rate  should  not  exceed  5Hz.    Consult  factory  for
higher  repetition  rates  or  high  pulse  load  applications.
See Figure 3.5 for the recommended interface circuit.

WARNING

IT IS EXTREMELY DANGEROUS TO USE THE

EXTERNAL INHIBIT TO STOP HIGH VOLTAGE

GENERATION FOR THE PURPOSE OF

SERVICING OR APPROACHING ANY AREA OF

THE LOAD CONSIDERED UNSAFE DURING

HIGH VOLTAGE OPERATION

EXTERNAL INTERLOCK:

The

External

Interlock

connections  are  provided  on  the  rear  panel  interface
connecter,  pin  3  and  pin  4,  intended  for  use  in  the
connection  to  a  customer  provided  and  implemented
external  safety  switch.    The  unit  will  not  operate  unless
the interlock circuit is closed.  If the interlock is not being
used  (use  is  highly  recommended),  a  jumper  must  be
installed.  During  high  voltage  operation,  opening  the
External  Interlock  will  cause  the  unit  to  revert  to  the
HIGH VOLTAGE OFF  mode.  Subsequent closing of the
interlock  circuit  will  NOT  return  the  unit  to  HIGH
VOLTAGE  ON  mode;  this  must  be  accomplished  by
depressing the HIGH VOLTAGE ON switch.  See Figure
3.6 for the recommended interface circuit.

ARC DETECT / ARC QUENCH /ARC COUNT:

The

ARC  Intervention  Circuitry  senses  dynamic  arcing  or
discharge  conditions  present  at  the  output  load  with  a
wide bandwidth current transformer coupled to the return
side of the high voltage multiplier.

The  instant  an  arc  is  detected  the  generation  of  high
voltage is electronically inhibited for 200mS; this is called
the  ARC  Quench  time  period.  After  the  200mS  period,
the  discharged  HV  output  (level  dependent  upon  arc
impedance,  arc  duration,  etc)  is  ramped  back  up  to  the
previous  set  level.    This  ramp  time  is  based  on  the
standard  200mS  Slow  Start  time  constant.  The  ARC
indicator  on  the  front  panel  will  illuminate  for
approximately  500mS  after  each  arc  has  occurred.  The
HV  INHIBIT  indicator  will  also  illuminate  for  500mS
indicating  that  the  output  is  being  inhibited  (ARC
Quench).

The  factory  default  setting  of  the  Arc  Intervention
circuitry  is  such  that  if  four  arcs  occur  in  a  ten  second
time  period  the  unit  will  shut  down  into  the  POWER
DOWN  mode  displaying  an  “ARC  Fault”.  ARC
parameters can be modified by using the digital interface
and  provided  GUI  but  changing  these  settings  can  have
serious consequences.

NOTE:  Making  changes  to  the  ARC  Intervention
Circuitry along with excessive arcing of the power supply
can  thermally  overheat  and  damage  the  internal  short
circuit  limiting  assembly.  Damage  to  the  power  supplies
internal short circuit limiting assembly is consider misuse
of  the  unit  and  repairs  will  not  be  covered  under  the
warranty. The ARC Intervention Circuitry is incorporated
and  configured  to  protect  the  power  supply  from
excessive  arcing,  make  changes  to  this  circuitry  at  your
own responsibility and risk.

REMOTE HIGH VOLTAGE ON & REMOTE HIGH
VOLTAGE OFF:

Signals are provided for remote

monitoring of the HIGH VOLTAGE ON and HIGH
VOLTAGE OFF status. See Figure 3.7 for recommended
interface.

3.3 Digital Interface (RS-

232/Ethernet)

The ST features standard RS-232 and Ethernet digital
interface capability. Please see Appendix A for complete
details on functionality and operation.

3.4 Reversible Polarity (1-10kV

Units Only) ST/STR Only

1 to 10kV units are inherently reversible by design but
still require a polarity selection to be made at time of
order. These units are air insulated and a simple wiring
change made in the high voltage multiplier section can
convert a positive polarity unit to a negative polarity unit,
or vice versa.

3.5 Multiple Chassis Systems

–

ST Only

Additional ST chassis can be connected in parallel to
achieve multiple 12kW increments of power to above and
beyond 100kW’s in a factory configured Master/Slave
arrangement. The Master unit retains its full feature front
panel while the Slave unit(s) have a Blank Front panel.
From an interfacing and functionality standpoint the
multiple chassis system behaves effectively like a single
chassis higher power unit. This technique provides
commonality of physically manageable hardware units
and possibility redundancy further enhancing system
uptime and reliability.