Associated Research 4500D Service manual

OPERATION AND SERVICE MANUAL

Hypot



II

MODEL 4500D

500 VA Enhanced

AC Only Hipot With Ground Continuity Chec k

SERIAL NUMBER

Model
4500D

Item 38088 Ver 1.08

© Associated Research, Inc. 2002

13860 West Laurel Drive

Lake Forest, Illinois 60045-4546

U.S.A.

Printed Feb. 11, 2003

i

5 YEAR WARRANTY POLICY

Associated Research, Inc., certifies that the instrument listed in this manual meets
or exceeds published manufacturing specifications. This instrument was calibrated using
standards that are traceable to the National Institute of Standards and Technology (NIST).

Your new instrument is warranted to be free from defects in workmanship and
material for a period of (1) year from date of shipment. Options and accessories that are
external to the instrument are warranted for a period of (90) days from date of shipment.
You must return the “Owners Registration Card” provided within (15) days from receipt
of your instrument.

AR recommends that your instrument be calibrated on a twelve month cycle.
Instruments purchased and used in North America only, may have their warranty
extended in one year increments to a maximum of (5) years provided they are returned to
AR at least annually for calibration and inspection. The annual calibration and
inspection must be performed annually every year following receipt of instrument. Any
instrument not calibrated and inspected annually will not be eligible for extended
warranty status. This extended warranty is non-transferable and is offered only to the
original purchaser.

A return material authorization (RMA) must be obtained from AR before
returning this instrument for warranty service. Please contact our Customer Support
Center at 1-800-858-TEST (8378) to obtain an RMA number. It is important that the
instrument is packed in its original container for safe transport. If the original container
in not available please contact our customer support center for proper instructions on
packaging. Damages sustained as a result of improper packaging will not be honored.
Transportation costs for the return of the inst rument for warranty service must be prepaid
by the customer. AR will assume the return freight costs when returning the instrument
to the customer. The return method will be at the discretion of Associated Research.

Except as provided herein, Associated Research makes no warranties to the
purchaser of this instrument and all other warranties, express or implied (including,
without limitation, merchantability or fitness for a particular purpose) are hereby
excluded, disclaimed and waived.

Any non-authorized modifications, tampering or physical damage will void your
warranty. Elimination of any connections in the earth grounding system or by-passing
any safety systems will void this warranty. This warranty does not cover batteries or
accessories not of Associated Research manufacture. Parts used must be parts that are
recommended by AR as an acceptable specified part. Use of non-authorized parts in the
repair of this instrument will void the warranty.

ii

TABLE OF CONTENTS

SECTION I OPERATORS MANUAL.................................................. 1

SAFETY............................................................................................... 2

INTRODUCTION................................................................................ 7

SPECIFICATIONS ............................................................................ 13

CONTROLS....................................................................................... 17

INSTALLATION............................................................................... 20

QUICKSTART................................................................................... 23

OPERATION...................................................................................... 26

OPTIONS ........................................................................................... 36

SECTION II SERVICE MANUAL ..................................................... 39

CALIBRATION................................................................................. 40

PARTS LIST ...................................................................................... 42

SCHEMATICS................................................................................... 43

iii

SECTION 1

OPERATORS MANUAL

SAFETY PRECAUTIONS REQUIRED FOR HIGH

SAFETY

VOLTAGE TESTING!

GENERAL:

This product and its related documentation must be reviewed for familiarization with
safety markings and instructions before operation. This product is a Safety Class I
instrument (provided with a protective earth terminal). Before applying power verify that
the instrument is set to the correct line voltage (115 or 230) and the correct fuse is
installed.

INSTRUCTION MANUAL SYMBOL. PLEASE REFER TO THE
INSTRUCTION MANUAL FOR SPECIFIC WARNING OR CAUTION
INFORMATION TO AVOID PERSONAL INJURY OR DAMAGE TO
THE PRODUCT.

INDICATES HAZARDOUS VOLTAGES MAY BE PRESENT

CHASSIS GROUND SYMBOL.

CALLS ATTENTION TO A PROCEDURE, PRACTICE, OR

WARNING

CONDITION, THAT COULD POSSIBLY CAUSE BODILY INJURY
OR DEATH.

CALLS ATTENTION TO A PROCEDURE, PRACTICE, OR

CAUTION

CONDITION, THAT COULD POSSIBLY CAUSE DAMAGE TO
EQUIPMENT OR PERMANENT LOSS OF DATA.

2

SAFETY

A Hipot produces voltages and currents that can cause harmful or fatal electric shock. To
prevent accidental injury or death, these safety procedures must be strictly observed when
handling and using the test instrument.

SERVICE AND MAINTENANCE
User Service

To prevent electric shock do not remove the instrument cover. There are no user
serviceable parts inside. Routine maintenance or cleaning of internal parts is not
necessary. Avoid the use of cleaning agents, chemicals, or liquids to clean the cabinet of
the instrument. Some chemicals are corrosive and may damage the finish of the
instrument or may damage plastic parts or lettering. Any external cleaning should be
done with a clean dry or slightly damp cloth. Application or spillage of liquid on the
instrument may penetrate the cabinet through the ventilation holes or damage the controls
and/or switches. Schematics, when provided, are for reference only. Any replacement
cables and high voltage components should be acquired directly from Associated
Research, Inc. Refer servicing to an Associated Research, Inc. authorized service center.

ASSOCIATED RESEARCH, INC.

13860 WEST LAUREL DRIVE

LAKE FOREST, IL 60045-4546 U.S.A.

!PHONE: [phone]

1 (800) 858-TEST (8378)

FAX: [phone]

E-MAIL : [e-mail]

.com

www.asresearch

Service Interval

The instrument and its power cord, test leads, and accessories must be returned at least
once a year to an Associated Research authorized service center for calibration and
inspection of safety related components. Associated Research will not be held liable for
injuries suffered if the instrument is not returned for its annual safety check and
maintained properly.

User Modifications

Unauthorized user modifications will void your warranty. Associated Research will not
be responsible for any injuries sustained due to unauthorized equipment modifications or
use of parts not specified by Associated Research. Instruments returned to Associated
Research with unsafe modifications will be returned to their original operating condition
at your expense.

TEST STATION
Location

Select an area away from the main stream of activity which employees do not walk
through in performing their normal duties. If this is not practical because of production
line flow, then the area should be roped off and marked for HIGH VOLTAGE
TESTING. No employees other than the test operators should be allowed inside.

3

SAFETY

If benches are placed back-to-back, be especially careful about the use of the bench
opposite the test station. Signs should be posted: “DANGER – HIGH VOLTAGE

TEST IN PROGRESS – UNAUTHORIZED PERSONNEL KEEP AWAY.”

Power

Dielectric Voltage-Withstand Test Equipment must be connected to a good ground. Be
certain that the power wiring to the test bench is properly polarized and that the proper
low resistance bonding to ground is in place.
Power to the test station should be arranged so that it can be shut off by one prominently
marked switch located at the entrance to the test area. In the event of an emergency,
anyone can cut off the power before entering the test area to offer assistance.

Work Area

Perform the tests on a nonconducting table or workbench, if possible.

There should not be any metal in the work area between the operator and the location
where products being tested will be positioned.

Position the tester so the operator does not have to reach over the product under test to
activate or adjust the tester. If the product or component being tested is small, it may be
possible to construct guards or an enclosure around the device to be tested. Construct the
guards of a non-conducting material such as clear acrylic, so that the item being tested is
within the guards or enclosure during the test. If possible, the guards or enclosure should
also contain safety switches that will not allow the tester to operate unless the guards are
in place or the enclosure closed.

Keep the area clean and uncluttered. All test equipment and test leads not absolut el y
necessary for the test should be removed from the test bench and put away. It should be
clear to both the operator and to any observers which product is being tested, and which
ones are waiting to be tested or have already been tested.

Do not perform Hipot tests in a combustible atmosphere or in any area where combustible
materials are present.

TEST OPERATOR QUALIFICATIONS

This instrument generates voltages and currents that can cause harmful or fatal electric
shock and must only be operated by a skilled worker trained in its use.

The operator should understand the electrical fundamentals of voltage, current, and
resistance.

Safety Procedures

Operators should be thoroughly trained to follow these and all other applicable safety
rules and procedures before they begin a test. Defeating any safety system should be
treated as a serious offense and should result in severe penalties, such as removal from

4

SAFETY

the Hipot testing job. Allowing unauthorized personnel in the area during a test should
also be dealt with as a serious offense.

Dress

Operators should not wear jewelry, which could accidentally complete a circuit.

Medical Restrictions

This instrument should not be operated by personnel with heart ailments or devices such
as pacemakers.

TEST PROCEDURES

!NEVER PERFORM A HIPOT TEST ON ENERGIZED CIRCUITRY OR
EQUIPMENT!

If the instrument has an external safety ground connection be sure that this is connected.
Always connect the return lead first, regardless of whether the item under test is a sample
of insulating material, a component tested with the high voltage test lead, or a cord­connected device with a two or three prong plug. The return lead should be connected
first for any type of hipot testing.

Plug in the high voltage test lead only when it is being used. Handle its clip only by the
insulator---never touch the clip directly. Be certain that the operator has control over any
remote test switches connected to the Hipot. Double-check the return and high voltage
connections to be certain that they are proper and secure.

NEVER TOUCH THE ITEM UNDER TEST OR ANYTHING

WARNING

When testing with DC, always discharge the capacitance of the item under test and
anything the high voltage may have contacted–such as test fixtures–before handling it or
disconnecting the test leads.

HOT STICK probes can be used to discharge any capacitance in the item under test as a
further safety precaution. A hot stick is a nonconducting rod about two feet long with a
metal probe at the end that is connected to a wire. To discharge the device under test, two
hot sticks are required. First, connect both probe wires to a good earth ground. Then
touch one probe tip to the same place that the return lead was connected. While holding
the first probe in place, touch the second probe tip to the same place where the high
voltage lead was connected.

CONNECTED TO IT WHILE HIGH VOLTAGE IS PRESENT
DURING THE HIPOT TEST.

5

KEY SAFETY POINTS TO REMEMBER:

••••

Keep unqualified and unauthorized personnel away from the test area.

••••

Arrange the test station in a safe and orderly manner.

••••

Never touch the product or connections during a test.

••••

In case of any problem, turn off the high voltage first.

••••

Properly discharge any item tested with DC before touching connections.

SAFETY

6

INTRODUCTION

GLOSSARY OF TERMS

(as used in this manual)

Alternating Current, AC:

U.S.A. 60 times per second, in other countries 50 times per second.

Breakdown:

arcing. If voltage is gradually raised, breakdown will begin suddenly at a certain voltage level. Current
flow is not directly proportional to voltage. Once breakdown current has flown, especially for a period of
time, a repeated application of voltage will often show breakdown beginning at a lower voltage than
initially.

Conductive:

more than 105 ohms per square.

Conductor:

a volume resistivity of no more than 103 ohm-cm.

Current:

milliamperes, microamperes, nanoamperes, or picoamperes. Symbol = I

Dielectric:

that a charge or voltage may appear across the two conductive materials.

The failure of insulation to effectively prevent the flow of current, sometimes evident by

Having a volume resistivity of no more than 103 ohm-cm or a surface resistivity of no

A solid or liquid material which has the ability to let cur rent pass through it, and which has

The movement of electrons through a conducto r. Current is measured in ampe res,

An insulating material which is positioned between two conductive materials in such a way

Direct Current, DC:

to be polarized and has one terminal which is always at a higher potential than the other.

Hipot Tester:
Hypot®:
Insulation:

used for the purpose of resisting current flow between conductors.

Common term for dielectric-withstand test equipment.

Registered trademark of Associated Research, Inc., for its dielectric-withstand test equipment.

Gas, liquid or solid material which has a volume resistivity of at least 10

Insulation Resistance Tester:

resistance’s in excess of 200 megohms. Usually employs a higher voltage power supply than used in
ohmmeters measuring up to 200 megohms.

Leakage:

capacitance. Current flow is directly proportional to voltage. The insulation and/or capacitance is thought
of as a constant impedance, unless breakdown occurs.

Resistance:

in the form of heat. The practical unit of resistance is the ohm. Symbol = R

Trip Point:

during a dielectric voltage-withstand test.

Voltage:

Symbol = V

AC or DC current flow through insulation and over its surfaces, and AC current flow through a

That property of a substance which impedes current and results in the dissipation of power

The minimum current flow required to cause an indication of unacceptable performance

Electrical pressure, the force which cause s current through an elec trical conductor.

Current which reverses direction on a regular basis, commonly in the

Current which flows in one direction only. The source of direct current is said

12

ohm-cm and is

An instrument or a function of an instrument capable of measuring

7

INTRODUCTION

INTRODUCTION

The importance of testing... User safety

In an era of soaring liability costs, original manufacturers of electrical and electronic
products must make sure every item is as safe as possible. All products must be designed
and built to prevent electric shock, even when users abuse the equipment or by-pass built
in safety features.

To meet recognized safety standards, one common test is the “dielectric voltage­withstand test”. Safety agencies which require compliance safety testing at both the
initial product design stage and for routine production line testing include: Underwriters
Laboratories, Inc. (UL), the Canadian Standards Association (CSA), the International
Electrotechnical Commission (IEC), the British Standards Institution (BSI), the
Association of German Electrical Engineers (VDE), the Japanese Standards Associat ion
(JSI). These same agencies may also require that an insulation resistance test and high
current ground bond test be performed.

The Dielectric Withstand (Hipot) Test....

The principle behind a dielectric voltage – withstand test is simple. If a product will
function when exposed to extremely adverse conditions, it can be assumed that the
product will function in normal operating circumstances.

The most common applications of the dielectric-wi thstand test are:

•

Design (performance) Testing.... determining design adequacy to meet service

conditions.

•

Production Line Testing.... detecting defects in material or workmanship during

processing.

•

Acceptance Testing.... proving minimum insulation requirements of purchased parts.

•

Repair Service Testing.... determine reliability and safety of equipment repairs.

The specific technique varies with each product, but basically, during a dielectric voltage
– withstand test, an electrical device is exposed to a voltage significantly higher than it
normally encounters. The high voltage is continued for a given period of time.

If, during the time the component is tested, stray current flow remains within specified
limits, the device is assumed to be safe under normal conditions. The basic product
design and use of the insulating material will protect the user against electrical shock.

The equipment used for this test, a dielectric-withstand tester, is often called a “hipot”
(for high potential tester). The “rule of thumb” for testing is to subject the product to
twice its normal operating voltage, plus 1,000 volts.

8

INTRODUCTION

However, specific products may be tested at much higher voltages than 2X operating
voltages + 1,000 volts. For example, a product designed to operate in the range between
100 to 240 volts, can be tested between 1,000 to 4,000 volts or higher. Most “double
insulated” products are tested at voltages much higher than the “rule of thumb”.

Testing during development and prototype stages is more stringent than production run
tests because the basic design of the product is being evaluated. Design tests usually are
performed on only a few samples of the product. Production tests are performed on each
and every item as it comes off the production line.

The hipot tester must also maintain an output voltage between 100% and 120% of
specification. The output voltage of the hipot must have a sinusoidal waveform with a
frequency between 40 to 70 Hz and has a peak waveform value that is not less than 1.3
and not more than 1.5 times the root-mean-square value.

Advantages and Disadvantages of AC Testing and DC Testing....

Please check with the Compliance Agency you are working with to see which of the two
type of voltages you are authorized to use. In some cases a Compliance Agency will
allow either AC or DC testing to be done. However in other cases the Compliance
Agency only allows for an AC test. If you are unsure which specification you must
comply with please contact our CUSTOMER SUPPORT GROUP at 1-800-858-TEST

(8378).

Many safety agency specifications allow either AC or DC voltages to be used during the
hipot test. When this is the case the manufacturer must make the decision on which type
of voltage to utilize. In order to do this it is important to understand the advantages and
the disadvantages of both AC and DC testing.

AC testing characteristics

Most items that are hipot tested have some amount of distributed capacitance. An AC
voltage cannot charge this capacitance so it continually reads the reactive current that
flows when AC is applied to a capacitive load.

AC testing advantages

1. AC testing is generally much more accepted by safety agencies than DC testing. The
main reason for this is that most items being hipot tested will operate at AC voltages and
AC hipot testing offers the advantage of stressing the insulation alternately in both
polarities which more closely simulates stresses the product will see in real use.

2. Since AC testing cannot charge a capacitive load the current reading remains consistent
from initial application of the voltage to the end of the test. Therefore, there is no need to
gradually bring up the voltage since there is no stabilization required to monitor the

9

INTRODUCTION

current reading. This means that unless the product is sensitive to a sudden application of
voltage the operator can immediately apply full voltage and read current without any wait
time.

3. Another advantage of AC testing is that since AC voltage cannot charge a load there is
no need to discharge the item under test after the test.

AC testing disadvantages

1. A key disadvantage of AC testing surfaces when testing capacitive products. Again,
since AC cannot charge the item under test, reactive current is constantly flowing. In
many cases the reactive component of the current can be much greater than the real
component due to actual leakage. This can make it very difficult to detect products that
have excessively high leakage current.

2. Another disadvantage of AC testing is that the hipot has to have the capability of
supplying reactive and leakage current continuously. This may require a current output
that is actually much higher than is really required to monitor leakage current and in most
cases is usually much higher than would be needed with DC testing. This can present
increased safety risks as operators are exposed to higher currents.

DC testing characteristics

During DC hipot testing the item under test is charged. The same test item capacitance
that causes reactive current in AC testing results in initial charging current which
exponentially drops to zero in DC testing.

DC testing advantages

1. Once the item under test is fully charged the only current flowing is true leakage
current. This allows a DC hipot tester to clearly display only the true leakage of the
product under test.

2. The other advantage to DC testing is that since the charging current only needs to be
applied momentarily the output power requirements of the DC hipot tester can typically
be much less than what would be required in an AC tester to test the same product.

DC testing disadvantages

1. Unless the item being tested has virtually no capacitance it is necessary to raise the
voltage gradually from zero to the full test voltage. The more capacitive the item the
more slowly the voltage must be raised. This is important since most DC hipots have
failure shut off circuitry which will indicate failure almost immediately if the total current
reaches the leakage threshold during the initial charging of the product under test.

10

INTRODUCTION

2. Since a DC hipot does charge the item under test it becomes necessary to discharge the
item after the test.

3. DC testing unlike AC testing only charges the insulation in one polarity. This becomes
a concern when testing products that will actually be used at AC voltages. This is a key
reason that some safety agencies do not accept DC testing as an alternative to AC.

4. When performing AC hipot tests the product under test is actually tested with peak
voltages that the hipot meter does not display. This is not the case with DC testing since
a sinewave is not generated when testing with direct current. In order to compensate for
this most safety agencies require that the equivalent DC test be performed at higher
voltages than the AC test. The multiplying factor is somewhat inconsistent between
agencies which can cause confusion concerning exactly what equivalent DC test voltage
is appropriate.

The Ground Continuity Test

The Ground Continuity test is checking to verify that there is low impedance path
between the chassis and the safety ground wire of the line cord. A low impedance ground
system is critical in ensuring that in the event of a product failure a circuit breaker on the
input line will act quickly to protect the user from any serious electrical shock.

International compliance agencies such as CSA, IEC, TÜV, VDE, BABT and others,
have requirements calling out this test. A low current test merely indicates that there is a
safety ground connection. It does not completely test the integrity of the connection that
would be accomplished by using much higher currents in the range from 10 to 30amps.
The high current test is known as a Ground Bond test.

The Ground Continuity test verifies that the ground circuit between the Continuity and
Return panel jacks on the Hypot II is below 1ohm while test at a current of 100mA. This
function can be enabled or disabled through software, when a ground circuit is not
provided on the device under test or test requirement are not needed.

The Insulation Resistance Test....

Some dielectric analyzers come with a built in insulation resistance tester. Typically, the
IR function provides test voltages from 500 to 1,000 volts DC and resistance ranges from
kilohms to gigaohms. This function allows manufacturers to comply with special
compliance regulations. BABT, TÜV and VDE are agencies that may require an IR test
on the product before a Hipot test is performed. This typically is not a production line
test but a performance design test.

The insulation resistance test is very similar to the hipot test. Instead of the go/no go
indication that you get with a hipot test the IR test gives you an insulation value usually in
Megohms. Typically, the higher the insulation resistance value the better the condition of
the insulation. The connections to perform the IR test are the same as the hipot test. The
measured value represents the equivalent resistance of all the insulation which exists

11