Transcript HEV Safety Considerations

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HEVs are nothing more than a traditional
automobile with advanced technologies that
deliver the same end result as a traditional
automobile, but with unique service hazards
Safety is of utmost importance when
approaching a HEV
Isolation of HV systems for routine system
service may be a necessity
ALWAYS refer to the manufacturer’s
recommended isolation techniques when
servicing an HEV
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When approaching an HEV, it is important to
recognize the potentially high voltage you may
be working around
Manufacturers have developed a way of
identifying high voltage systems with brightly
colored markings
2009 Prius A/C compressor with
ORANGE sheathing surrounding
HV supply to compressor
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Sheathing has been categorized into colors that
indicate voltage levels present
Black – 12-42V
 Yellow or Blue – ~42V
 Orange – 144-650V
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Information courtesy of
Jim Halderman
Information/images courtesy of Jim Halderman
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While hybrids may look and feel similar to
traditional vehicles, the introduction of HV to
the vehicle creates unique work risks
For example, the THS-II system on the 2004+
Toyota Prius can exhibit 500V under operation
Identifying the location of HV components on
any HEV is key to working safely
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Gloves
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Must be routinely inspected (as in EACH use!)
Must have a Class 0 rating (safe up to 1000V)
Should have protective capabilities beyond
insulation, i.e., puncture resistance
 This is why traditional HEV service gloves have a
leather our glove and an insulating Class 0 rated
primary glove
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DISCARD if damaged!
Recommended replacement every 6 months
Do NOT gamble when dealing with high voltage!
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Testing gloves
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Blow air into glove and roll it to inspect for fractures
that may allow HV to penetrate
MUST be free from water, sweat, oil and other
potentially conductive and combustible/flammable
chemicals
 Glove Dust may be used to reduce sweating in gloves
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Tools
Insulated tools, which commonly have been tested at
10kV, are recommended
 Typically have a safe working voltage of 1000V
 Are relatively inexpensive ($500-$1000 per set)
 Should be routinely inspected
 Should be used as recommended by the
manufacturer
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Clothing
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Sleeved shirts
 Short sleeve vs. long sleeve
Jewelry should be removed as it is conductive
 Should be free from water, sweat, oil and other
potentially conductive and combustible/flammable
chemicals
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Digital Multimeters
CAT III rating recommended
 According to D. Marinucci (MOTOR, 2008),
automotive manufacturers have not endorsed a
particular rating
 CAT III-CAT IV recommended by leading industry
experts with extensive HEV service research
experience
 Rating will be indicated on the face of the meter
 Gloves MUST be worn when testing HV circuitry
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Multimeters
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A meter with insulation testing capabilities is also
recommend to test HV insulation properties
 Do NOT insulation test yourself as the meter supplies
HIGH VOLTAGE and low current to check
conductivity (Fluke 1587 outputs 1017VDC @ 1.60mA)
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Leads must also be CAT rated appropriately for the
systems you are evaluating
Test Voltage should be selectable
 Fluke 1587 ranges are: 50V, 100V, 250V, 500V, 1000V
Measured Resistance
HV Output Warning
In Progress
DMM Voltage
Output
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On HEVs, it is important to note that some may
start with the key in the proximity of the
vehicle
Toyotas use a READY light to indicate the
engine may start
MEA Article by Dave Scaler
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In the event the auxiliary battery dies, you can
remove the lock cylinder key to enter the
vehicle
Chrome Toyota symbol
identifies this key as a
Smart Key
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Brake pedal must be
depressed to start
Prius
Note READY light
on dash
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Known good (tested and inspected gloves)
must be used to isolate HV circuit
Refer to manufacturer’s information to locate
the HV disconnect plug
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Even though the plug may be removed
mechanically, HV is still available at the battery
terminals
NEVER service the HV system without first
verifying HV is no longer present (with a
properly rated DMM)
HV Disconnect
1. Pull Up
2. Rotate
3. Remove
Wait 10 minutes, test for HV and proceed if no HV is
present before servicing vehicle
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It is possible to charge a HV battery, but not
very common
Typically, the 12V (auxiliary battery) will fail
and cause a no start condition
Jump starting the 12V battery varies from mfr.
to mfr.