N39
Veris Application Note
DC Current Transducers in Electroplating Operations
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Follow safe electrical work practices. See NFPA 70E in the USA, or applicable local codes.
This equipment must only be installed and serviced by qualified electrical personnel.
Read, understand and follow the instructions before installing this product.
Turn off all power supplying equipment before working on or inside the equipment.
Use a properly rated voltage sensing device to confirm power is off.
DO NOT DEPEND ON THIS PRODUCT FOR VOLTAGE INDICATION
• Only install this product on insulated conductors.
DC Power Supply
Figure 2
+
HAZARD OF ELECTRIC SHOCK, EXPLOSION, OR ARC FLASH
electron flow
Failure to follow these instructions will result in death or serious injury.
T R IE S
IN D U S 97223
V E R I Sl a n d , O r e g o n 0 0 - 3 5 4 - 8 5 5 6
P o rt
1 -8
electron flow
_
DANGER
In most electroplating operations, the metallic film that forms on the cathode is not
perfectly uniform in thickness. If a smooth surface is needed, the current flowing
from the DC power supply can be reversed for a brief time, causing the two electrodes
to switch their polarity. The top layer of metal atoms on the object’s surface will
oxidize back to their ionic state, return to the electrolyte solution, and flow toward
the opposite electrode. Figure 2 illustrates this reversal process, called Periodic
Reverse Current electroplating.
971 ens or
tS
n
C u rre
200A DC
!
Current
Flow
4-20
mA
VDC
12-24
Power
Gnd
Span
The information provided herein is intended to supplement the
knowledge required of an electrician trained in high voltage
installations. There is no intent to foresee all possible variables
in individual situations, nor to provide all training needed to
perform these tasks. The installer is ultimately responsible to
assure that a particular installation will be and remain safe and
operable under the specific conditions encountered.
In electroplating applications, an anode and a cathode are connected to an external
DC power supply, such as a battery or rectifier, and placed into an electrolyte solution.
The object to be plated is used as the cathode. When DC power is flowing through
the electrodes, the metal cations migrate through the liquid solution toward the
cathode. At the cathode surface, these metal ions are reduced to their metallic (zero
valence) state and are deposited on the cathode surface. In this manner, a thin film of
the desired metal forms across the entire surface of the object.
Anode
(object to be plated)
Cathode
M
M
M
Top-most layer of metal
atoms oxidize and leave
the surface of the object.
_
M+
M+
_
M+
M+
_
Electrolyte solution in contact with both electrodes.
Contains ions of the metal to be plated onto the cathode.
Repeatedly switching the DC current flow direction in this manner will even the
plated surface on the object.
A DC current sensor with Pulse Effect Technology™ can improve the accuracy and
reliability of DC sensing. These sensors have the added benefit of bidirectional
amperage sensing. This allows continuous monitoring for load drops, even when the
DC current is travelling in the reverse direction. Faults are detected immediately, at
any point in the electroplating operation.
A DC current sensor allows monitoring of the power supply, in order to quickly
identify faults or drops in load. This reduces the downtime associated with repairs.
Figure 1 shows a basic diagram of an electroplating apparatus in operation, with a DC
current sensor in place to monitor the load from the power supply.
Figure 1
DC Power Supply
_
electron flow
+
electron flow
T R IE S
IN D U S 97223
V E R I Sl a n d , O r e g o n 0 0 - 3 5 4 - 8 5 5 6
P o rt
1 -8
971 ens or
tS
n
C u rre
200A DC
!
Current
Flow
4-20
mA
VDC
12-24
Power
Gnd
Span
Cathode
(object to be plated)
Anode
M
M
M
M
Metal plated surface
forms on the object
VN39 Page 1
_
M+
M+
_
_
M+
Electrolyte solution in contact with both electrodes.
Contains ions of the metal to be plated onto the cathode (M+).
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