Krohn-Hite 3210C User manual

Model 3210C
100 Ampere
AC Current Standard
Operating Manual

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3210C
OPERATORS
MANUAL
Serial No.______________

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3210C
OPERATORS
MANUAL
Copyright © 1998
Krohn-Hite Corporation
15 Jonathan Drive Unit 4
Brockton, Massachusetts 02301
E-mail: [e-mail]
www.krohn-hite.com
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any
form by any means, electronic, mechanical photocopying, recording, or otherwise, without the prior written
permission of Krohn-Hite Corporation .
Printed in U.S.A.
Version 4.21
Revised March 2001
Information furnished in this manual is believed to be accurate and reliable. However, no responsibility is assumed
by Krohn-Hite Corporation for its use; nor for any infringements of patents or other rights of third parties which
may result from its use.

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TABLE OF CONTENTS
iv List of Drawings
v Limited Warranty
vi Factory Service Request and Authorization
vii Packing Suggestions
I DESCRIPTION AND SPECIFICATIONS
1.1.0 General Description
1.2.0 Applications
1.3.0 General Specifications
1.4.0 Input Specifications
1.5.0 Output Specifications
II INSTALLATION
2.1.0 Mounting
2.2.0 AC Power Input Considerations
III OPERATION OF INSTRUMENT
3.1.0 Controls & Indicators
3.2.0 10 Amp Range Output Connections
3.3.0 100 Amp Range Output Connections
3.4.0 Input Connections
IV THEORY OF OPERATION
4.1.0 Introduction
4.2.0 Power Supply
4.3.0 Control Circuit
4.4.0 A.G.C. Circuit
4.5.0 Power Amplifier
V CALIBRATION PROCEDURE
5.1.0 Equipment Required
5.2.0 P.A. Idle Current Adjustment
5.3.0 Input Rectifier Zero
5.4.0 Output Rectifier Zero
5.5.0 100 Amp Output Calibration
5.6.0 10 Amp Output Calibration
VI PARTS LIST
6.1.0 Replacement Parts for 3210C
NOTE: Errata and addendum (if any) will appear in the back of this manual.

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LIST OF DRAWINGS
Description Drawing Number
Watt Hour Meter Set up A-4559
Schematic - Power Supply & Control Circuit B-3944E
Schematic - 100 Amp AC Transconductance Amplifier B-3945J
Layout - 3210C Adjustments & Test Points B-4051C
Reference Drawing 930727A

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LIMITED WARRANTY
The Krohn-Hite Corporation (K-H) warrants to the original purchaser each instrument
manufactured by them to be free from defects in material and workmanship. This warranty is
limited to servicing, repairing and/or replacing any instrument or part thereof returned to the K-H
factory for that purpose in accordance with the instructions set forth below; and furthermore to
repair or replace all materials, except tubes, fuses, transistors and other semiconductor devices
which shall within one year of shipment to the original purchaser be returned to the K-H factory
and upon examination be deemed defective.
K-H instruments may not be returned to the factory under the terms of this warranty
without the prior authorization of the K-H Service Department. All instruments returned to K-H
for service hereunder should be carefully packed and shipped. All transportation charges shall be
paid by the purchaser.
K-H reserves the right to discontinue instruments without notice and to make changes to
any instrument at any time without incurring any obligation to so modify instruments previously
sold.
This warranty is expressly in lieu of all other obligations or liabilities on the part of K-H.
No other person or persons is authorized to assume in the behalf of K-H any liability in the
connection with the sale of its instruments.
CAUTION: The instrument you have purchased is a precision instrument
manufactured under exacting standards. Any attempts to repair, modify or
otherwise tamper with the instrument by anyone other than an K-H employee or
authorized representative may result in this warranty becoming void.

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FACTORY SERVICE REQUEST
AND
AUTHORIZATION
WARRANTY SERVICE
Instruments may be returned only on prior authorization. Please obtain a RETURN
AUTHORIZATION NUMBER either directly from the factory or from an authorized K-H
Representative. (See General Information below.)
CHARGEABLE REPAIRS
If requested, an estimate of charges will be submitted prior to repairs. We suggest that you
request a RETURN AUTHORIZATION NUMBER to facilitate handling.
GENERAL INFORMATION
A) Please provide the following information in order to expedite the repair:
1) Indicate MODEL
2) Serial Number
3 Complete description of the trouble:
Symptoms, measurements taken, equipment used, lash-up procedures, attempted
repairs, suspected location of failure and any other pertinent information.
B) Freight Charges must be PREPAID.
C) The RETURN AUTHORIZATION NUMBER should be noted on your documentation.
D) See Packing Suggestions - next page.

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PACKING SUGGESTION
Although your K-H instrument is built for laboratory, production environment and some field
environment, it is NOT ruggedized. Therefore ...
1. Be sure the carton is STRONG enough to carry the weight of the instrument, e.g. use
double wall corrugation.
2. Be sure the carton is LARGE enough to allow for sufficient packing material, e.g., at least
2 inches all around the instrument. The packing material should be able to be compressed
and then return to its approximate original volume.
3. For better handling, the shipment should always be by AIR FREIGHT (except for short
distances). You might use either UPS "blue label" or common air freight carrier, second
day air.
Please do not bounce it across the country in a truck. It may not hurt it, but it certainly is
not going to do a laboratory instrument much good.
4. QUESTIONS? Just contact us. We will be pleased to help you.

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SECTION I
1.0.0 DESCRIPTION AND APPLICATIONS
1.1.0 General Description
1.1.1 The 3210C, AC 100 ampere calibrator is an accurate voltage to current amplifier or
transconductance amplifier. The application of a precise voltage to the input terminals
produces a proportional current into any load within the compliance range of the
instrument. The AC input voltage band width is 40 Hz to 500 Hz.
1.1.2 The unit is laboratory calibrated with instruments and load resistors traceable to U. S.
National Institute of Standards & Technology.
1.1.3 Applying power and connecting the load to the proper set of output terminals prepares the
unit for operation.
1.1.4 The Model 3210C is equipped for rack mounting in a standard 19 inch rack. It is
completely enclosed in dust covers and therefore suitable for bench top use. Tilt bale is
available on request.
1.1.5 The overall size is 7H x 19W x 17D inches. It weighs 43 pounds. A 3-prong
American-European standard detachable power cord is used.
1.1.6 The instrument has been designed to be easily transported from one location to another
and will be within operational specification within 30 minutes after power is applied.
1.2.0 Applications:
Direct calibration of Watt Meters and Watt-hour Meters (with applicable Voltage
Standard), Meter Shunts, AC Current Meters, Current to Voltage Transducers, Current to
Pneumatic Transducers, DMMs, and relay coil current testing.

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1.3.0 General Specifications
Power Requirement: 117 Vac or 220 Vac, 50-60 Hz. + 5%, 300 W
Temperature Coefficient: 50 ppm/ º C
Operating Temperature: 10 to 40 C
Weight: 43 lbs.; 19.5 kg
Shipping Weight: 50 lbs.; 22.7 kg
Dimensions: 7H x 19W x 17D inches
17.8H x 48.3W x 43.2D cm
Certification: Certificate of Compliance traceability to U.S.
National Institute of Standards & Technology.
Protection: The unit will automatically go into a standby mode when the maximum
compliance voltage is exceeded or when a malfunction has occurred.
1.4.0 Input Specifications
Input Voltages: 0 to 11 Vac (rms), 10 V rms input Produces
full scale output of current range.
Input Impedance: 10 k
AC Band Width: 40 Hz to 500 Hz

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Voltage Compliance vs Current
0.5
0.75
1
1.25
10 20 30 40 50 60 70 80 90 100
Amps
Volts
1.5.0 Output Specifications
Ranges: 10 A rms - maximum output 11 A rms
100 A rms - maximum output 110 A rms
Accuracy: ±(0.05% of setting +0.05% of range)
Power Output: ~50 Watts at maximum output.
Compliance Voltage: 10 A Range 5.0 Vac rms maximum at 10 Amps
100 A Range 0.5 Vac rms maximum at 100 Amps
Load Regulation: +0.002% short-circuit to full compliance
Line Regulation: +0.0005% for +10% line change
Distortion: 0.25% of setting + 0.1% of range as
measured at phase out terminals
Ripple & Noise, rms: 0.05% of setting +0.05% of range *
* - non-additive

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SECTION II
2.0.0 INSTALLATION
2.1.0 Mounting
2.1.1 Krohn-Hite Corporation instruments may be obtained in several
case configurations.
2.1.2 Portable units are rugged, light weight, completely enclosed in a dust tight case supplied
with a carrying handle.
2.1.3 Rack mountable instruments are designed primarily for mounting in the standard 19"
relay rack. When installing in the rack, it is recommended that nylon inserts be placed
between the cup washer and the front panel to prevent scratching of the paint.
2.2.0 AC Power Input Considerations
2.2.1 All instruments are supplied with a standard three (3) prong polarized plug and
power cable.
2.2.2 A multi-tap transformer is provided, however it is set to 115 Vac or 230 Vac via the slide
switch on the Rear panel. Other voltages can be accommodated by making the proper
selections of the transformer taps.

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SECTION III
3.0.0 OPERATION OF INSTRUMENT
3.1.0 Controls and Indicators
3.1.1 A 110 V - 220 V switch is located on the rear panel.
3.1.2 A "push on" "push off" power switch with mechanical indicator is located on the front
panel.
3.1.3 Momentary contact STANDBY and OPERATE switches and their associated indicators
are located on the front panel. The unit will automatically power-on to the standby state.
CAUTION: OUTPUT CONNECTIONS - Only one set of output terminals may
be used at one time.
3.2.0 10 Amp Range Output Connections
3.2.1 Number 18 AWG wire or larger is appropriate for the 10 AMP range.
3.3.0 100 Amp Range Output Connections
3.3.1 Number 1/0 AWG wire is appropriate for the 100 AMP range. The flexible welding
cable is convenient for some applications.
3.3.2 Mating Male Connectors
MANUFACTURER: SUPERIOR ELECTRIC COMPANY
PART NUMBER: PP250GR (RED)
PART NUMBER: PP250GB (BLACK)
3.4.0 Input Connections
Connect a sinewave source of the desired amplitude, (10 Vac input) for full range current
output and frequency to the input terminals.